Question
Question: If \(\cos x + \cos^{2}x = 1,\) then the value of \(\sin^{2}x + \sin^{4}x\) is...
If cosx+cos2x=1, then the value of sin2x+sin4x is
A
1
B
– 1
C
0
D
2
Answer
1
Explanation
Solution
cosx+cos2x=1⇒cosx=sin2x
∴sin2x+sin4x=cosx+cos2x=1.
If cosx+cos2x=1, then the value of sin2x+sin4x is
1
– 1
0
2
1
cosx+cos2x=1⇒cosx=sin2x
∴sin2x+sin4x=cosx+cos2x=1.