Question

The maximum value of the expression 1/(sin^2x + 3sinx cox + 5 cos^2 x)?

Answer 1

I guess 1

Answer 2

the answer should be 2

Answer 3

\[\frac{1}{(1-\cos^2x)+3sinx \space cosx + 5 \cos^2x}\]

Answer 4

\[\frac{1}{1+4\cos^2x +3sinx \space cosx}\]