Find the coefficient of x^4 in 3x^3-5x^4 + x-7

With finding limits of multi variable !

White shapes and black shapes are used in a game. some of the shapes are circles. while the rest are squares. the ratio of the number of white shapes to the number of black shapes is 5: 11. the ratio of the number of white cicrles to the number of white squares is 3: 7. the ratio of the number of black circles to the number of black squres is 3: 8. work out what fraction of all the shapes are circles.

Find the solution on the interval [0, 2pi)