Need help. waht is the answer? thank you sir.

Question

If C is given by x=2cost, y=2sint, z=πt, 0≤t≤π, evaluate : ∫_C(x+z)ds.

Answer 1

ds=[√(x'²+y'²+z'²)]dt

ds=[√(4sin²t+4cos²t+π²)]dt

ds=[√(4+π²)]dt,,,,,which is a constant times dt

so I=√(4+π²)∫(2cos(t)+πt)dt ,,,t from 0 to π

I=√(4+π²)*[2sin(t)+πt²/2],,, t from 0 to π

I=√(4+π²)*π³/2

I≈57.7