Question

cos²20°+ cos²70 by
Sin 57° +Sin 33°​

Answer 1

Step-by-step explanation:

$\frac{ { \cos}^{2} 20 + { \cos}^{2}70 }{ \sin57 + \sin33 } \\ = \frac{ { \cos(90 - 70)}^{2} + { \cos}^{2}70 }{ \sin(90 - 33) + \sin33 } \\ = \frac{ { \sin}^{2}70 + { \cos}^{2}70 }{ \cos33 + \sin33} \\ = \frac{1}{ \cos33 + \sin33 }$