Step-by-step explanation:
Rearrange the equations to solve.
cos(-3 • pi) = -1
cos((-3pi) / 4 radians) = -0.707
cos(5 • pi) = -1
cos((5pi) / 4 radians) = -0.707
They are the same because when multiplied, they are the same value, and always will be that way. They also have the same identity if you simplify and compare the results of that equation.
