Question

5sin²α+3cos²α / 3sin²α-5cos²α = if tgα=√2

Answer 1

Tgα = tan(α) = sqrt(2)/1 = opposite/ adjacent
opposite = sqrt(2)
adjacent = 1
hypotenuse = sqrt(opposite^2 + adjacent^2)
= sqrt(sqrt(2)^2 + 1^2) = sqrt(3)

sin(α) = opposite/hypotenuse
= sqrt(2)/sqrt(3)

cos(α) = adjacent/hypotenuse
= 1/sqrt(3)

now we can calculate the value of
5sin²α+3cos²α / 3sin²α-5cos²α
... do the math