Simplify the following expression.
$cos^230°+ cos^2 40° + cos^2 50° + cos^2 60°$
Answer & explanation
Correct answer: option 4
$cos^230°+ cos^2 40° + cos^2 50° + cos^2 60°$
{ we know,
If A + B = 90° Then cosA = sinB }
= $sin^260°+sin^2 50° + cos^2 50° + cos^2 60°$
= $sin^260°+cos^2 60° + sin^2 50° + cos^2 50°$
= 1 + 1 ( sin²θ + cos²θ = 1 )
= 2