Question $1[$Definite integrals: Elementary Functions$]$: For each of the following functions evaluate the definite integral

${\displaystyle \underset{a}{\overset{b}{}}}f(x)dx$

for the indicated values of a and $b.$

a$)f(x)=x^3,a=4,b=16$

b$)f(x)=(x^{2}1{)}^2,a=1,b=2$

c$)f(x)=cos(\frac{x}{4}),a=0,b=1$