The question is:

9(i) Sketch, on a single diagram showing values of x from -180degs to +180degs, the graph of y=tanx and y= 4cos x.

The equation tan x = 4cos x

has two roots in the interval -180degs\< +\<180degs. These are denoted by a(alpha) and b(pheta), where a<b

(ii) Show a and b on your sketch, and express b in terms of a.

(iii) Show that the equation tan x = 4cos x may be written as 4sin^2 x + sin x - 4 =0

Hence find the value of b-a, correct to the nearest degree.

If you can help me in any way possible, i have drawn the graph!