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!