Chapter 3: Derivatives - Section 3.5 - Derivatives of Trigonometric Functions - Exercises 3.5 - Page 141: 34

a. $-2sin(x)$, b. $9cos(x)$,

Recall the formulas $\frac{d}{dx}(sin(x))=cos(x)$, $\frac{d}{dx}(cos(x))=-sin(x)$, a. $y'=-2cos(x)$, $y''=2sin(x)$, $y'''=2cos(x)$, $y^{(4)}=-2sin(x)$, b. $y'=-9sin(x)$, $y''=-9cos(x)$, $y'''=9sin(x)$, $y^{(4)}=9cos(x)$,