Learn All Concepts of Chapter 1 Class 9 - FREE. Check - Chapter 1 Class 9 Maths

We do not leave an irrational number in the denominator.

So, we rationalise the denominator. Let us look at some examples

Last updated at Sept. 11, 2020 by Teachoo

Learn All Concepts of Chapter 1 Class 9 - FREE. Check - Chapter 1 Class 9 Maths

We do not leave an irrational number in the denominator.

So, we rationalise the denominator. Let us look at some examples

Transcript

Some Identities (โ๐)^2=๐ โ(๐^2 )=๐ โ๐๐=โ๐ รโ๐ โ(๐/๐)=โ๐/โ๐ (โ๐โโ๐)(โ๐+โ๐)=๐โ๐ (๐โโ๐)(๐+โ๐)=๐^2โ๐ (โ๐+โ๐)^2=๐+๐+2โ๐๐ (โ๐+โ๐)(โ๐+โ๐)=โ๐๐+โ๐๐ + โ๐๐ + โ๐๐

Rationalising

Rationalising denominator of irrational number
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Add (3โ2+7โ3) and (โ2โ5โ3)

Divide 5โ11 by 3โ33

Multiply 2โ15 by 7โ5

Simplify (โ5+โ7)^2

Simplify (โ4โโ13)(โ4+โ13)

Simplify (9โโ3)(9+โ3)

Simplify (3โ5โ5โ2)(4โ5+3โ2)

Rationalise the denominator of 8/โ7

Rationalise the denominator of 1/((8 + 5โ2))

Multiple Choice Questions - Chapter 1 Class 9 Maths

Simplify (7โ3)/(โ10 + โ3)โ(2โ5)/(โ6 + โ5)โ(3โ2)/(โ15 + 3โ2)

If a and b are rational numbers and (โ11 โ โ7)/(โ11 + โ7) = a โ bโ77, find the value of a and b

Example 17

Example 18

Find the values of a and b if (7 + 3โ5)/(3 + โ5) โ (7 โ 3โ5)/(3 โ โ5) = a+โ5 b

Ex 1.5,5 Important

If x = 1/(2 โ โ3), find the value of x^3 โ 2x^2 โ 7x + 5

Example 19 Important

If a = 5 + 2โ6 and b = 1/a, then what will be the value of a^2+b^2 ?

Example 20

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

About the Author

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 9 years. He provides courses for Maths and Science at Teachoo.