Question

Rationalise the denominator of 1 by 4+✓5​

Answer 1

1 by 4+ √5

= 1× 4+√5. =4+√5.

4+√5 × 4+√5= 4 Square+ √5square

= 4+√5.

16 + 5

= 4+√5

21

Step-by-step explanation:

4 Square =16

in √ 5 square we cancel √ by Square .

I hope this is helpful to you.

Plz mark as a brilliant answer please.

Answer 2

Hello mate..

Here Is Your Answer:

We know that (a+√b) (a-√b) = a² - b

Multiplying the numerator and denominator of

$\bold{ \frac{1}{4 + \sqrt{5} } \: by \: 4 - \sqrt{5} }$

$\bold{ \frac{1}{4 + \sqrt{5} } \times \frac{4 - \sqrt{5} }{4 - \sqrt{5} } = \frac{4 - \sqrt{5} }{{4}^{2} - {( \sqrt{5} )}^{2} } }$

$\bold{ = \frac{4 - \sqrt{5} }{16 - 5} } \\ \bold = > { \frac{4 - \sqrt{5} }{11} }$

HOPE THIS HELPS YOU..