Impossible! Do you think you can understand it?
Solve for y:
2 x+cos(y) = 0
Subtract 2 x from both sides:
cos(y) = -2 x
Take the inverse cosine of both sides:
Answer: | y = cos^(-1)(-2 x)+2 pi n_1 for n_1 element Z
or y = 2 pi n_2-cos^(-1)(-2 x) for n_2 element Z
