Rationalise the denominators of the following:
(i) \(\frac{1 }{ \sqrt{7 }}\)
(ii) \(\frac{1 }{ \sqrt{7 }-\sqrt6}\)
(iii) \(\frac{1 }{ \sqrt{5}+\sqrt2}\)
(iv) \(\frac{1 }{ \sqrt{7}-2}\)
Rationalise the denominators of the following:
(i) \(\frac{1 }{ \sqrt{7 }}\)
(ii) \(\frac{1 }{ \sqrt{7 }-\sqrt6}\)
(iii) \(\frac{1 }{ \sqrt{5}+\sqrt2}\)
(iv) \(\frac{1 }{ \sqrt{7}-2}\)
Solution and Explanation
(i) \(\frac{1 }{ \sqrt{7 }}\) =\(\frac{1}{\sqrt7}=\frac{1}{\sqrt7} ×\frac{ √7 }{√7}\)
= \(\frac{ √7 }{√7}\)
(ii) \(\frac{1 }{ \sqrt{7 }-\sqrt6}\)
\(= \frac{1}{ (√7 + √6)} ×\frac{(√7 - √6)}{(√7 + √6)}\)
= \(\frac{(√7 - √6)}{7 - 6}=\sqrt7+\sqrt6\)
(iii) \(\frac{1 }{ \sqrt{7}-2}\)
\(\frac{\sqrt5+\sqrt2}{3}\)
(iv) \(\frac{1 }{ \sqrt{7}-2}\)
\(=\frac{\sqrt7+2}{7-2}=\frac{\sqrt7+2}{3}\)
Top Questions on Operations on Real Numbers
- Let α and β be real numbers. Consider a \(3 \times 3\) matrix A such that \(A^2 = 3A + \alpha I\). If \(A^4 = 21A + \beta I\), then
- JEE Main - 2023
- Mathematics
- Operations on Real Numbers
- Let \(λ ≠ 0\) be a real number. Let α, β be the roots of the equation \(14x^2 – 31x + 3λ = 0\) and α, γ be the roots of the equation \(35x^2 – 53x + 4λ = 0\). Then \(\frac{3\alpha}{\beta}\) and \(\frac{4\alpha}{\lambda}\) are the roots of the equation
- JEE Main - 2023
- Mathematics
- Operations on Real Numbers
For real number a, b (a > b > 0), let
\(\text{{Area}} \left\{ (x, y) : x^2 + y^2 \leq a^2 \text{{ and }} \frac{x^2}{a^2} + \frac{y^2}{b^2} \geq 1 \right\} = 30\pi\)
and
\(\text{{Area}} \left\{ (x, y) : x^2 + y^2 \geq b^2 \text{{ and }} \frac{x^2}{a^2} + \frac{y^2}{b^2} \leq 1 \right\} = 18\pi\)
Then the value of (a – b)2 is equal to _____.- JEE Main - 2022
- Mathematics
- Operations on Real Numbers
- Let for some real numbers \(α\) and \(β\), \(a = α – iβ\). If the system of equations \(4ix + (1 + i) y = 0\) and \(8\bigg(cosx\frac{2π}{3}+i\;sin\frac{2π}{3}\bigg)x+\bar ay=0 \)has more than one solution, then \(\frac{α}{β}\) is equal to
- JEE Main - 2022
- Mathematics
- Operations on Real Numbers
- Let A = [1, 2, 3, 4, 5], m be the number of relations such as 4x ≤ 5y XRY and n be the minimum number of elements to be added from A × A to make a symmetric relation. Then the value of n + m.
- JEE Main
- Mathematics
- Operations on Real Numbers
Questions Asked in CBSE Class IX exam
A driver of a car travelling at \(52\) \(km \;h^{–1}\) applies the brakes Shade the area on the graph that represents the distance travelled by the car during the period.
Which part of the graph represents uniform motion of the car?- CBSE Class IX
- Graphical Representation of Motion
- Verify : (i) x 3 + y 3 = (x + y) (x 2 – xy + y 2 ) (ii) x 3 – y 3 = (x – y) (x 2 + xy + y 2 ).
- CBSE Class IX
- Algebraic Identities
- An object of mass 1 kg travelling in a straight line with a velocity of 10 m s–1 collides with, and sticks to, a stationary wooden block of mass 5 kg. Then they both move off together in the same straight line. Calculate the total momentum just before the impact and just after the impact. Also, calculate the velocity of the combined object.
- CBSE Class IX
- Inertia and Mass
- Discuss what these phrases mean to you.
(i) a yellow wood
(ii) it was grassy and wanted wear
(iii) the passing there
(iv) leaves no step had trodden black
(v) how way leads on to way- CBSE Class IX
- The fun they had
- What do you think Dinamani is the name of? Give a reason for your answer.
- CBSE Class IX
- My childhood