1)

$\displaystyle \int_C 3x^2yzds$

$\displaystyle C: x=t, y=t^2, z=\frac{2}{3}t^3 ; (0 \leq t \leq 1) $

My solution

$\displaystyle \int_0^1 2t^7 \sqrt{1+4t^2+4t^4}dt = \frac{13}{20}$

2)

$\displaystyle \int_C (x^2+y^2)dx - xdy$

$\displaystyle C: x^2+y^2 = 1 ; (0 \leq t \leq \frac{ \pi}{2})$

My solution:

$\displaystyle \int_0^{\frac{ \pi}{2}} (-sint - cos^2t)dt$

Is correct ?