Question

If sin A+sin²A=1 then cos²A + cos ^4A=
​

Answer 1

Given:

sin A+sin²A=1

To find:

cos²A + cos ^4A= ?

we know cos²A+sin²A=1

⇒cos²A=1-sin²A---------(1)

according to the problem,

sinA+sin²A=1

⇒sinA=1-sin²A--------(2)

By comparing both equations,

we get, sinA = cos²A

so,,,,, cos²A+cos⁴A = sinA+sin²A = 1