Question

The sin of 40 degrees is equal to the _ of 50 degrees

Answer 1

cos(50)

Explanation:

Let's see, so we've got 50+40=90 and as you know it makes them complementary to each others. now if raise sin40 in power of 2, it's sum with cos²α is gonna be 1.

`\sin(40)^(2) + { \cos( \alpha ) }^(2) = 1 = = = > \\ 0.41 + { \cos( \alpha ) }^(2) = 1 = = > { \cos( \alpha ) }^(2) = 0.58 = = = \\ \cos( \alpha ) = 0.76 = = > \\ \alpha = 50`