ft cot 2t pi4 VERIFY EACH OF TRIG IDENTITY 2 sinz X sin4
Solution
1. 2sin2x= sin4x-cos4x +1
Starting with the right side
sin4x-cos4x +1
(sin2x)2-(cos2x)2+1
(sin2x+cos2x)(sin2x-cos2x)+1
sin2x-cos2x+1
sin2x+sin2x=2sin2x which is equal to left side
2. cscx/(cot x + tan x) = cos x
Starting with the left side
cscx/(cotx + tanx)
1/sinx/(cosx/sinx + sinx/cosx)
1/sinx/((cos2x+sin2x))/sinx cos x
cos x/ 1=cos x that is equal to the right side
