Question

Sina+ sinA = 1 Toebot & 1 then find the value of cos²A+cos⁴A=?​

Answer 1

Answer:

cosA(1+sinA)+cosA(1-sinA)/(1-sinA)(1+sinA)=4

cosA(1+sinA+1-sinA)/1-sin²A=4

cosA(2)/cos²A=4 [as sin²A+cos²A=1]

2/cosA=4

1/cosA=2

cosA=1/2

cosA=cos60°

∴A=60°