Question

Find the value of tan 2A, if cos 3A = sin 45

Answer 1

♧♧HERE IS YOUR ANSWER♧♧

Given :

cos3A = sin45

=> cos3A = sin(90 - 45)

=> cos3A = cos45

So, 3A = 45, by inverting the cosine.

=> A = 15

So, we see that :

A = 15°

Now,

tan2A

= tan(2 × 15)°

= tan30°

= 1/(√3)

= 0.577 (approximately)

Remember :

sin(90 - θ) = cosθ

cos(90 - θ) = sinθ

tan(90 - θ) = cotθ

cot(90 - θ) = tanθ

sec(90 - θ) = cosecθ

cosec(90 - θ) = secθ

♧♧HOPE IT HELPS YOU♧♧

Answer 2

Hey mate !!!

Cos 3A = sin 45 °

Cos3A = sin (90° -45°)

Cos3A = 45°



cosA = > 15 °



now , tan 2A =>


tan 15*2. => tan 30 °


tan 30° = > 1/√3


hope it helps :

thanks