Question

If sec A=√2, find 3 cot² A+2 sin²A/tan²A -cos ²A

Answer 1

here,
A=45°

then apply it to the equation,

=cos^2 45°+(2sin^2A + 2cos^2A)
_________________________
1 -1

=(1/root2)^2 +2
___________
0

=0


Hence proved