Question

.If sin A + sin

2A = 1, then cos

2A+ cos

4A= ?​

Answer 1

Answer:

1

Step-by-step explanation:

sinA+sin² =1

sinA=1−sin²A

sinA=cos²A

Now

cos²A+cos²A.cos²A

=sinA+sin²A

=1

Answer 2

I think you entered a wrong question, It will be:

$SinA+Sin^{2}A =1, then,Cos^{2}A+Cos^{4}A=?$·

Answer:

$Cos^{2}A+Cos^{4}A=1$

Step-by-step explanation:

Given,

$SinA+Sin^{2}A=1\\=>SinA=1-Sin^{2}A\\=>SinA=Cos^{2}A$

Squaring both sides, We get

$Sin^{2}A=Cos^{4}A\\=>1-Cos^{2}A=Cos^{4}A\\=>1=Cos^{4}A+Cos^{2}A$