Advertisements
Advertisements
Question
The number obtained on rationalising the denominator of `1/(sqrt(7) - 2)` is ______.
Options
`(sqrt(7) + 2)/3`
`(sqrt(7) - 2)/3`
`(sqrt(7) + 2)/5`
`(sqrt(7) + 2)/45`
Solution
The number obtained on rationalising the denominator of `1/(sqrt(7) - 2)` is `underlinebb((sqrt(7) + 2)/3)`.
Explanation:
Rationalizing the denominator as follows:
`1/(sqrt(7) - 2) = 1/(sqrt(7) - 2) xx (sqrt(7) + 2)/(sqrt(7) + 2)`
= `(sqrt(7) + 2)/((sqrt(7))^2 - 2^2)`
= `(sqrt(7) + 2)/(7 - 4)`
= `(sqrt(7) + 2)/3`
APPEARS IN
RELATED QUESTIONS
Classify the following numbers as rational or irrational:
`2-sqrt5`
Rationalise the denominator of the following:
`3/(2sqrt5)`
Find the value to three places of decimals of the following. It is given that
`sqrt2 = 1.414`, `sqrt3 = 1.732`, `sqrt5 = 2.236` and `sqrt10 = 3.162`
`(sqrt5 + 1)/sqrt2`
Express the following with rational denominator:
`1/(3 + sqrt2)`
if `x = (sqrt3 + 1)/2` find the value of `4x^2 +2x^2 - 8x + 7`
Write the reciprocal of \[5 + \sqrt{2}\].
`root(4)root(3)(2^2)` equals to ______.
Simplify the following:
`(sqrt(3) - sqrt(2))^2`
Rationalise the denominator of the following:
`sqrt(40)/sqrt(3)`
Rationalise the denominator in the following and hence evaluate by taking `sqrt(2) = 1.414, sqrt(3) = 1.732` and `sqrt(5) = 2.236`, upto three places of decimal.
`4/sqrt(3)`
