Question

the value of 1+tan²15/1-tan²15​

Answer 1

Question

1+tan²15/1-tan²15

Solution

$\bold{\dfrac{(1 - tan² 15°)}{( 1+tan² 15°)}}$

use formula,

$\bold{cos2Ø={\dfrac{(1-tan?Ø)}{(1+tan?Ø)}}}$

let Ø = 15°then ,

$\bold{cos2 x 15°={\dfrac{ (1-tan²15°)}{(1+tan 15°)}}}$

so,

$\bold{\dfrac{ (1-tan²15°)}{(1+tan² 15°)}}$ =cos30°

=$\bold{\pink{\dfrac{\sqrt3}{2}}}$

hope it helps☺️