CUET Preparation Today
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
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