If cos 20=m determine the values of the following in terms of m. (a) cos(-200) (b)sin 250 (c)sin 20 thanks

Answer 1

can you not use the same name for all your posts?

cos(-200) = cos(200) = -cos(20) = -m

work with the other angles in a similar way. Draw triangles on the axes to help see the transformation formulas.