Question

if a= 1+√7 find 1/a after rationalisation

please tell me with explaination​

Answer 1

Step-by-step explanation:

.............m..............

Answer 2

Answer:

Step-by-step explanation:

a= 1 + √7

also can be written as a = √7 + 1

∴ 1/a= 1/(√7 +1)

Multiply R.H.S with (√7 - 1) in both Numerator and Denominator

1/a = (√7 -1) / [(√7 -1)(√7 + 1)]

The R.H.S denominator is of the form a² - b² = (a-b)(a+b)

So in the above equation a=√7 and b=1

Hence, 1/a = (√7 - 1) / [(√7)² - (1)²]

∴ 1/a = (√7 - 1) / (7 - 1)

∴ 1/a = (√7 - 1) / 6

or 1/a = (√7/6) - (1/6)