Question

What is cos(x°)= cos(57°)cos(94°)-sin(57°)sin(94°)

Answer 1

Note that the given cos(57°)cos(94°)-sin(57°)sin(94°) resembles the formula

cos a cos b - sin a sin b, which is cos (a+b).

Therefore, cos(57°)cos(94°)-sin(57°)sin(94° = cos (57+94) = cos 151.