12. In a right triangle ABC with C = 90, if [ BC| = 4, |AB| = 6, evaluate the following (a) AC. Page 2 (b) cos A. (c) cos B. (d) sin A. (e) tan B. 13. Graph the functions sin x, cos x, tan x. (If you have difficulty in this, refer the graphs in the book from Section 4.3 and 4.4) In particular, pay attention to the periods and odd/even proper- ties of these functions