17: (x-a) square+(y-b) square = rsquare a =1b = 2r5, so the equation of the element is (x+1) square+(y-2) square = 5square/25.

18: Solution Because f(x)= the radical 3 sinx-cosx = 2 sin (x-30) and because X belongs to R,-1 is less than or equal to 1, so -2 is less than or equal to 2 sin (x-30).

So the range of F(X) is (-2,2).