Give details in the derivation of expressions (2), Sec. 37, for the derivatives of sin z and cosz. 1. (a) With the aid of expression (4), Sec. 37, show that Then use relations (3), Sec. 37, to show...

Give details in the derivation of expressions (2), Sec. 37, for the derivatives of sin z and cosz.

1. (a) With the aid of expression (4), Sec. 37, show that

Then use relations (3), Sec. 37, to show how it follows that

(b) Use the results in part (a) and the fact that

to obtain the identity

in Sec. 37.