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Example 20 - Chapter 1 Class 9 Number Systems (Term 1)
Last updated at Jan. 31, 2022 by Teachoo
Rationalising
Rationalising denominator of irrational number
Add (3β2+7β3) and (β2β5β3)
Divide 5β11 by 3β33
Multiply 2β15 by 7β5
Simplify (β5+β7)^2
Simplify (β4ββ13)(β4+β13)
Simplify (9ββ3)(9+β3)
Simplify (3β5β5β2)(4β5+3β2)
Rationalise the denominator of 8/β7
Rationalise the denominator of 1/((8 + 5β2))
Simplify (7β3)/(β10 + β3)β(2β5)/(β6 + β5)β(3β2)/(β15 + 3β2)
Multiple Choice Questions - Chapter 1 Class 9 Maths
If a and b are rational numbers and (β11 β β7)/(β11 + β7) = a β bβ77, find the value of a and b
Example 17
Example 18
Find the values of a and b if (7 + 3β5)/(3 + β5) β (7 β 3β5)/(3 β β5) = a+β5 b
If x = 1/(2 β β3), find the value of x^3 β 2x^2 β 7x + 5
Ex 1.5, 5 (i)
If a = 5 + 2β6 and b = 1/a, then what will be the value of a^2+b^2 ?
Example 19
Example 20 Important You are here
Chapter 1 Class 9 Number Systems
Concept wise
- Rational numbers - Definition
- Finding rational number between two numbers
- Irrational Numbers
- Simplifying real numbers
-
Rationalising
- Laws of exponents
- Finding decimal expansion
- Expressing decimal in p/q
- Classifiying rational/irrational
- Finding irrational numbers b/w two numbers
- Real numbers on a number line
Transcript
Example 20 Rationalize the denominator of 1/(7 + 3β2 ). 1/(7 + 3β2 ) = 1/(7 + 3β2) Γ (π β πβπ)/(π β πβπ) = (7 β 3β2)/(7 + 3β2)(7 β 3β2) = (7 β 3β2)/((π)^π β (πβπ)^π ) = (7 β 3β2)/(49 β (3 Γ 3 Γ β2 Γ β2) ) = (7 β 3β2)/(49 β (9 Γ 2) ) ( As (a + b)(a β b) = a2 β b2 ) = (7 β 3β2)/(49 β 18) = (π β πβπ)/ππ
