Simplify the following expression. $cos^230°+ cos^2 40° + cos^2 50° + cos^2 60°$

$\frac{3}{2}$ 1 $\frac{5}{2}$ 2

2

$cos^230°+ cos^2 40° + cos^2 50° + cos^2 60°$ { 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