Question

the value of 4(cos2 50*+cos2 40*) is

Answer 1

It is 4
$\: \: \: \: 4( \ { \cos }^{2} 50 + {cos}^{2}40) \\ = 4({cos}^{2}50 + {sin}^{2}(90 - 50)) \\ = 4( {cos}^{2}50 + {sin}^{2}50 \\ = 4(1) \\ = 4$
So 4 is the right answer