Subjexct: Mathematics CONTENTS C lass: IX S.No. Topics Page No. 1. Number System 1-3 5. Polynomials 3 6-5 6 3. Coordinate Geometry 5 7-6 4. Linear Equation in two Variable 63-7 1 5. Introduction of Euclid's Geometry 7-7 7 6. Lines and Angles 7 8-8 8 7. Triangles 8 9-9 8 8. Quadrilateral 9 9-1 1 4 9. Area of parallelograms and triangle 11 5-18 10. Circle 19-155 11. Constructions 1 56-164 1. Heron's Formula 1 65-17 13. Surface Area & Volume 173-181 14. Statistics 1 8-19 7 15. Probability 198-04 16. Proof In Mathematics 05-11 17. Mathematical Modeling 1-0» > NUMBER SYSTEM «< CLASSIFICATION OF NUMBERS (I) Natural numbers: Set of all non-fractional number from 1 to + oo, N = {1,,3,4,...}. (II) Whole num bers: Set of numbers from 0 to +, W = {0,1,,3,4,...}. (III) Integers: Set of all-non fractional numbers from o to + o, I or Z = (..., -3,-,-1,0,1,,3,...}. (IV) Rational num bers: These are real numbers which can be expressed in the form of p/q, where p and q are integers and q i= - 0. e.g. /3, 37/15,-17/19. All natural numbers, whole numbers and integers are rational. Rational numbers include all Integers (without any decimal part to it), terminating fractions (fractions in which the decimal parts terminating e.g. 0.75, - 0.0 etc.) and also non-terminating but recurring decimals e.g. 0.666..., -.333..., etc. Fractions:
(a) Common fraction : Fractions whose denominator is not 10. (b) Decimal fraction : Fractions whose denominator is 10 or any power of 10. 3 (c) Proper fraction : Numerator < Denominator i.e.. 5 (d) Improper fraction : Numerator > Denominator i.e.. (e) Mixed fraction : Consists of integral as well as fractional part i.e. 3-7-. /3 (f) Compound fraction : Fraction whose numerator and denominator themselves are fractions. i.e. "5/7. Improper fraction can be written in the form of mixed fractions. (v) Irrational Numbers : All real number which are not rational are irrational numbers. These are non-recurring as well as nonterminating type of decimal numbers e.g. V",^4, + ~J3,^ + V 3,^^3 etc. (vi) Real numbers : Number which can represent actual physical quantities in a meaningful way are known as real numbers. These can be represented on the number line. Number line in geometrical straight line with arbitrarily defined zero (origin). (vii) Prime number : All natural numbers that have one and itself only as their factors are called prime numbers i.e. prime numbers are exactly divisible by 1 and themselves. e.g.,3,5,7,11,13,17,19,3...etc. If P is the set of prime number then P = {,3,5,7...}. (viii) Composite numbers : All natural number, which are not prime are composite numbers. If C is the set of composite number then C = {4,6,8,9,10,1,... }. 1 is neither prime nor composite number. (ix) Co-prime numbers : If the H.C.F. of the given numbers (not necessarily prime) is 1 then they are known as co-prime numbers. e.g. 4, 9, are co-prime as H.C.F. of (4, 9) = 1. Any two consecutive numbers will always be co-prime. (x) Even Numbers : All integers which are divisible by are called even numbers. Even numbers are denoted by the expression n, where n is any integer. So, if E is a set even numbers, then E = {..., -4, -, 0,, 4,...}. (xi) Odd Numbers: All integers which are not divisible by are called odd numbers. Odd numbers are denoted by the general expression n - 1 where n is any integer. If O is a set of odd numbers, then O = {..., - 5, -3, -1, 1, 3, 5,...}. (xii) Imaginary Numbers: All the numbers whose square is negative are called imaginary numbers. e.g. 3i, 4i, i, where i = V 1. (xiii) Complex Numbers : The combined form of real and imaginary numbers is known as complex numbers. It is denoted by Z = A + ib where A is real part and B is imaginary part of Z and A, B e R. The set of complex number is the super set of all the sets of numbers. IDENTIFICATION PRIME NUMBER Step 1 : Find approximate square root of given number.
Step : Divide the given number by prime numbers less than approximate square root of number. If given number is not divisible by any of this prime number then the number is prime otherwise not. Ex.1 571, is it a prime? Approximate square root of 571 = 4. Prime number < 4 are, 3, 5, 7, 11, 13, 17, 19, & 3. But 571 is not divisible by any of these prime numbers so 571 is a prime number. Ex. Is 1 prime or composite number? 1 is neither prime nor composite number. REPRESENTATIO FO RATIONAL NUMBER OF A REAL NUMBER LINE (i) 3/7 Divide a unit into 7 equal parts. (ii) 13 7 (iii) - - 9 (a) Decimal Number (Terminating) (i).5 (ii).65 (process of magnification) Ex.3 Visualize the representation of 5.37 on the number line upto 5 decimal place. i.e. 5.37777. 5 o i <o rr in <o rs cq q* 6 I lo in i o l o O i o o o to i i l lo r~~- 5 3 co co CO co co ^ o i n i b i n i o 5. 4 t o t o \ f cm ^ i f l >o r-'. 5. 3 7 r n > 0 fo c o <T5 e o < o i i f l i n U ) lo t o t o CO V R & 5. 3 8 uj> pc 5 ^ 3 7 7 ^ - ^ 3 CO \ 1 \ r~-- \ CO \ lo \ 5. 3 7 8 1! \ s
(b) Find Rational Numbers Between Two Integral Numbers : Ex.4 Find 4 rational numbers between and 3. Steps : (i) Write and 3 multipling in Nr and Dr with (4+1). (ii) i^. x (4 + 1) _ 1 & 3 _ 3 x (4 + 1) _ 15 (4 +1) 5 (4 +1) 5 / \ f-y, f,, 11 1 13 14 (iii) So, the four required numbers are,,,. 5 5 5 5 Ex.5 Ex.6 Find three rational no's between a and b (a < b). ^ ^ a < b a + a < b + a a < a + b a + b Again, a < b ^ a + b < b + b. ^ a + b < b a + b < b. a + b, a < -------< b. i + b i.e. lies between a and b. 1 + b Hence 1 st rational number between a and b is For next rational number a + b a + a + b a + - 3a + b 3a + b a + b, a < -------- < --------< b. 4 4 a + b +b a + b + b a + 3b Next, x 4 3a + b a + b a + 3b a< < < < b, and continues like this. 4 4 1 1 Find 3 rational numbers between &. 3 1 st Method 1 1 ----1---- 3 " + 3 6 _5_ 1 1 A I 3. 1, 1 5 4 + 5 - + 3 1 = 1 9_ 4 1 _9 5_ 1 3. 4. 1, 5 1 -------1----- 1 6_ 1 + 1 _ 11 4 1 _9 5_ 1 1 1 3, 4, 1, 4,
r 8 9 10 11 1 ( 8 1 1 Verify : < < < <.1as = & 4 4 4 4 4 ^ 4 3 nd Method : Find n rational numbers between a and b (a < b). b - a (i) Find d = n +1 (ii) 1st rational number will be a + d. nd rational number will be a + d. 3rd rational number will be a + 3d and so on.. nth rational number is a + nd. 3 4 Ex.7 Find 5 rational number between and 5 5 4-3 3 4 b - a 5 5 15 1 1 Here, a =,b = d = -------= 5 = x = 5' 5 n +1 5 +1 5 6 30, 3 1 19, 3 1st a + b +, nd a + d +, 1 5 30 0 5 30 3 3 1 3 4 3rd a + 3d \-----, 4th a + 4d \------, 3 5 30 30 4 5 30 30 ^ 3 5 3 5th a + 5d I-----. 5 5 30 30 RATIONAL NUMBER IN DECIMAL REPRESENTATION (a) Terminating Decimal : 1 In this a finite number of digit occurs after decimal i.e. = 0.5, 0.6875, 0.15 etc. (b) Non-Terminating and Repeating (Recurring Decimal) : In this a set of digits or a digit is repeated continuously. Ex.8 0.6666--------------- 0.6. 3 5 Ex.9 0.454545------------- 0.45. 11 PROPERTIES OF RATIONAL NUMBER If a,b,c are three rational numbers. (i) Commutative property of addition. a + b = b + a(ii) Associative property of addition (a+b)+c = a+(b+c) (iii) Additive inverse a + (-a) = 0 0 is identity element, -a is called additive inverse of a. (iv) Commutative property of multiplications a.b. = b.a. (v) Associative property of multiplication (a.b).c = a.(b.c) (vi) Multiplicative inverse (a)x (-1 j 1
1 1 is called multiplicative identity and is called multiplicative inverse of a or reciprocal of a. a (vii) Distributive property a.(b+c) = a.b + a.c L.H.S. * R.H.S. Hence in contradicts our assumption that + 43 rational. + 43 is irrational. Ex.9 Prove that 43-4 is an irrational number Let 43-4 r where r be a rational number Squaring both sides ^ (V 3 -V ) r ^ ^ 3 + - V6 = r 5 - V6 = r Here, 5-46 is an irrational number but r is a rational number L.H.S. * R.H.S. Hence it contradicts our assumption that 43-4 is a rational number. (b) Irrational Number in Decimal Form : 4 = 1.41413... i.e. it is not-recurring as well as non-terminating. 43 = 1.73050807... i.e. it is non-recurring as well as non-terminating. Ex.10 Ex.11 Insert an irrational number between and 3. V x 3 46 Find two irrational number between and.5. 1st Method : -J x.5 S Since there is no rational number whose square is 5. So 45 is irrational.. Also -^ x 45 is a irrational number. nd Method :.101001000100001... is between and 5 and it is non-recurring as well as non-terminating. Also,.01001000100001... and so on. Ex.1 Find two irrational number between 4 and 43. 1st Method : 4 4 x43 V46 46 44 x 46 4 x 46 Irrational number between4 and V6 nd Method : As 4 = 1.4141356... and 43 = 1.73050808... As, 43 >4 and 4 has 4 in the 1st place of decimal while 43 has 7 is the 1st place of decimal. 1.501001000100001..., 1.601001000100001... etc. are in between 4 and 43
Ex.13 Find two irrational number between 0.1 and 0.13. 0.101001000100001..., 0.1101001000100001...etc. Ex.14 Find two irrational number between 0.3030030003... and 0.3010010001... 0.30000000... 0.30030030003... etc. Ex.15 Find two rational number between 0.333333... and 0.5555555555. 1st place is same. nd place is 3 & 5. 3rd place is in both. 4 th place is 3 & 5. Let a number = 0.5, it falls between the two irrational number. Also a number = 0.55 an so on. (c) Irrational Number on a Number Line : Ex.16 Plot 4^43^4546 on a number line. Another Method for : (i) Plot V,V3 So, OC = V and OD = 43 (ii) Plot V5,V6,V7V8 o c = V5 o d = V6 o h = 4 7... (d) Properties of Irrational Number : (i) Negative of an irrational number is an irrational number e.g. - 43 - ^5 are irrational. (ii) Sum and difference of a rational and an irrational number is always an irrational number. (iii) Sum and difference of two irrational numbers is either rational or irrational number. (iv) Product of a non-zero rational number with an irrational number is either rational or irrationals (v) Product of an irrational with a irrational is not always irrational. Ex.17 Two number's are and 4 3, then Sum = + 43, is an irrational number. Difference = - 4 3, is an irrational number. Also 43 - is an irrational number.
Ex.18 Two number's are 4 and ^ 3, then Sum = 4 + ^3, is an irrational number. Difference = 4 - ^3, is an irrational number. Ex.19 Two irrational numbers are 43,-43, then Sum = 43 + (- 43) 0 which is rational. Difference = 43 - (- 43) 43, which is irrational. Ex.0 Two irrational numbers are + 43 and - 4 3, then Sum = ( + 43)+ ( - 43) 4, a rational number Two irrational numbers are 43 + 3mV3-3 Difference = 43 + 3-43 + 3 6, a rational number Ex.1 Two irrational numbers are 43-4,43 + 4, then Sum = 4 3-4 + 4 3 + 4 43, an irrational Ex. is a rational number and 43 is an irrational. x 43 43, an irrational. Ex.3 0 a rational and 43 an irrational. 0 x -J3 = 0, a rational. Ex.4 4 r 4 r 4 x V 3 V3 is an irrational. 3 3 43 Ex.5 43x43 V 3 x 3 49 3 a rational number. Ex.6 43 x 34 x 3>/3 x 646 and irrational number. Ex.7 ^ 3 x ^3 ^3 x 3 ^3^ 3 a rational number. Ex.8 ( + 43 J - 4 3 ) () - (43) 4-3 1 a rational number.
Ex.9 ( + V3 )( + V3) ( + V3) () +(V3 f + () x^/3) 4 + 3 + 4V3 = 7 + 4 ^ 3 an irrational number NOTE : (i) V - # - V, it is not a irrational number. (ii) V - x V -3 * (>/- x - 3 V6) Instead V -,V- 3 are called Imaginary numbers. >/- ^a/, where i ( = iota) = V - 1 (A) i = -1 (B) i3 = i x i = (-1) x i = -i (C) i4 = i x i = (-1) x (-1) = 1 (iii) Numbers of the type (a + ib) are called complex numbers where (a, b) e R.e.g. + 3i, - + 4i, -3i, 11-4i, are complex numbers. GEOMETRICAL REPRESENTATION OF REAL NUMBERS To represent any real number of number line we follows the following steps : STEP I : Obtain the positive real number x (say). STEP II : Draw a line and mark a point A on it. STEP III : Mark a point B on the line such that AB = x units. STEP IV : From point B mark a distance of 1 unit and mark the new point as C. STEP V : Find the mid - point of AC and mark the point as O. STEP VI : Draw a circle with centre O and radius OC. STEP VII : Draw a line perpendicular to AC passing through B and intersecting the semi circle at D. Length BD is equal to -/x.
4. Examine whether the following numbers are rational or irrational : (i) ( - 4 3 f (ii) (V + V 3) (iii) (3 + V )(3-4 ) (iv) J 3 + 1 5. Represent V8.3 on the number line. 6. Represent ( + V3) on the number line. 7. Prove that (V + V 5) is an irrational number. 8. Prove that 4 7 is not a rational number. 9. Prove that ( + V ) is an irrational number. 10. Multiply V7a3b c4 x ^18a7b 9c x ^79ab1c. 11. Express the following in the form of p/ q. (i) 0.3 (ii) 0.37 (iii) 0.54 (iv) 0.05 (v) 1.3 (vi) 0.61 1. Simplify : 0.4 +.018 SURDS» > NUMBER SYSTEM «< Any irrational number of the form is given a special name surd. Where 'a' is called radicand, it should always be a rational number. Also the symbol ^ is called the radical sign and the index n is called order of the surd. n a is read as 'nth root a' and can also be written as a n. (a) Some Identical Surds : (i) 44 is a surd as radicand is a rational number. Similar examples ^ 5,^ 1,^7^Vl,... (i) 43 is a surd (as surd + rational number will give a surd) Similar examples 43 + 1,^ 3 + 1,...
(iii) V 7 - W 3 is a surd as 7-4>/3 is a perfect square of ( - V3) Similar examples -y/7+4/3,4 9-4V 5,^9 + 4 ^ 5,... 1 ^ 1 "\3 1 (i) is a surd as 3 3 6 ^3 V v / Similar examples ^ ^ 5,4 ^ 6,... (b) Some Expression are not Surds : (i) 8 because ^8 ^ 3, which is a rational number. (ii) V + V3 because + V3 is not a perfect square. (iii) yf3 because radicand is an irrational number. LAWS OF SURDS (i) ( ^ ^ a e.g. (A) ^8 ^ (B) ^81 V34 3 (ii) ^a x ^ b [Here order should be same] e.g. (A) 4 x ^ 6 ^ x 6 ^1 but, ^ 3 x ^6 ^ V3 x 6 [Because order is not same] 1st make their order same and then you can multiply. (iii) n a + n b n - Vb (iv) V ^ a m a V v a e.g. = ^ 7 7 848 (v) n a nxpap [Important for changing order of surds] or, ^ nxpamxp e.g. make its order 6, then 3x- 6x. e.g. ^ 6 make its order 15, then ^6 3^^61x5.
OPERATION OF SURDS (a) Addition and Subtraction of Surds : Addition and subtraction of surds are possible only when order and radicand are same i.e. only for surds. Ex.1 Simplify (i) V 6-4 1 6 +V96 15 4 6-4 6 x 6 W 16 x 6 [Bring surd in simples form] = 1546-646+446 = (15-6 + 4 )V6 = 13V6 Ans. (ii) 5^50 + 7^16-143^54 5^15 x + 7^8 x -1 4 ^ 7 x 5 x 5^ + 7 x ^ - 1 4 x 3 x ^ (5 +14-4)^ -3 ^ Ans. (ii) 5^50 + 7^16-143^54 5^15 x + 7^8 x -1 4 ^ 7 x 5 x 5^ + 7 x ^ - 1 4 x 3 x 4 (5 +14-4)^ -33/ Ans. 5 1 x 3 (iii) W 3 + 3^48 - - J - 1 W 3 + 3^16 x 3 ---- V3 V3 x 3 C -1 =W 3 +3 x 4V3 x - V 3 3 443+ 1V3 V3 6 f 4+1-6 Ans. (b) M ultiplication and Division of Surds : Ex. (i) 44 x ^ 3 4 x ^3 x 11 ^H (i) ^ x 43 1 4 x ^ 4 x 33 1 16 x 7 ^ 43 Ex.3 Simplify V8a5b x ^4ab Hint : ^ 8 W x ^ 4 a4b4 41V V ^ *. Ans.
Ex.4 Divide 4 + 00 ^ (4) ^00 ^(QQ) V65 (c) Comparison of Surds : It is clear that if x > y > Qand n > 1 is a positive integer then x > nfy. Ex.5 Ex.6 16 > 1, 3 5 > 5 and so on. Which is greater is each of the following : (i) 1 6 and 8 L.C.M. of 3 and 5 15. (ii),, '1 V3 L.C.M. of and 3 is 6. 3/6 ^57776 8 3^5 85 a551 1 1 6 and 6 V8 V 9 1 1 As 8 < 9 - > - 8 9 757776 > 151 so, 6 > 8 i > i f Ex.7 Arrange, 3 and 5 is ascending order. L.C.M. of, 3, 4 is 1. x6 164 3 181 5 4x3 53 115 As, 64 < 81 < 15. ^^64 < 181 < 115 < 3 < 5 Ex.8 Which is greater 7-3 or 5-1? 7-3 ( 7-3 ) ( 7 + 3 ) _ 7-3 4 ( 7 + 3) 7 + 3 7 + 3 (5-1 )( 5 + 1) _ 5-1 _ 4 And, 5-1 ( 5 + 1) 5 +1 5 +1 Now, we know that 7 > 5 and 3 > 1, add So, 7 + 3 > 5 +1
1 1 4 4 V 7+ V3 V 5 +1 V 7+ V3 V 5 +1 V 7 - V3 < V5-1 So, V 5-1 > V 7 -V 3 RATIONALIZATION OF SURDS Rationalizing factor product of two surds is a rational number then each of them is called the rationalizing factor (R.F.) of the other. The process of converting a surd to a rational number by using an appropriate multiplier is known as rationalization. Some examples : (i) R.F. of Va is Va Va X-y/a a). s/a.?/: r. s/a x ^ a i. (ii) R.F. of V ais^a Va > (iii) R.F. of Va + VbisVa - Vb & vice versa (a/: + Vb )(Va - Vb) a - b]. (iv) R.F. of a + Vb is a - Vb & vice versa [/.(a + Vb )(a- V b) a - b] (v) R.F. of Va + Vb is ^Va" - Vab + ^bj (Va + V b - Vab + ^b (Va ) + (Vb ) a + b which is rational. (vi) R.F. of (Va + Vb + Vc )is (Va + Vb - Vc )nd (a + b - c + Vab) Ex.9 Find the R.G. (rationalizing factor) of the following : (i) V i0 (ii) V1 (iii) V16 (iv) V I (v) V16 (vi) V16 (vii) + V3 (viii) 7 - ^V3 (ix) 3V3 + V (x) V3 + V (xi) 1+ V +V3 (i) V10 [.-.Vi0 x V i0 V 10 x 10 10] as 10 is rational number.. R.F. of V10 is V10 Ans. (ii). V1 First write it's simplest from i.e. V 3. Now find R.F. (i.e. R.F. of V3 is V 3 ) R.F. of V1 is V3 Ans. (iii) V16 Simplest from of V16 is 9>/. R.F. of V is V. R.F. of V16 is V Ans. (iv) V4 V4 X V! 4 R.F. of V i is V4 Ans. (v). V16 Simplest from of V16 is V Now R.F. of V is V R.F. of V16 is V Ans.
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