Question

7sin squareA+3cos squareA=4 then find value of A

Answer 1

HEYA !

Given that,

7sin²A + 3cos²A = 4

Using Formula [ cos²A = 1 - sin²A ]
We get

7sin²A + 3 ( 1 - sin²A ) = 4

→ 7sin²A + 3 - 3sin²A = 4

→ 4sin²A = 4 - 3

→ 4sin²A = 1

→sin²A = 1/4

→ sinA = √(1/4)

→ sinA = 1/2

→ sinA = sin30°

By comparing , We get

$\boxed{ \text{ A = 30\degree }} \: \: \: \: \: \: \: \: \: \: \: \mathbf{Ans.}$