Question

trigonometry question

Answer 1

hey !!!

Sinx + sin3x
----------------
cosx + cos3x

by using this formula sinC + sinD = 2 sin(C +D)/2 ×cos(C - D)/2

and , cosC + cosD = 2cos(C + D)/2 × cos(C -D)/2

like that ..

2sin(x+3x )/2×cos(C-D)/2
-----------------------------------
2cos(C+D)/2 ×cos(C-D)/2

=> 2sin(4x)/2
--------------------
2cos(C+D)/2

=> 2sin2x/2cos2x

=> tan2x RHS prooved

hope it helps!!!

₹Rajukumar111