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Active Calculus - Multivariable

Activity 13.3.4.
Let \(\vF(x,y) = \langle y^2,2xy+3\rangle\text{.}\)
(a)
Let \(C_1\) be the portion of the graph of \(y=2x^3+3x^2-12x-15\) from \((-2,5)\) to \((3,30)\text{.}\) Calculate \(\int_{C_1}\vF\cdot d\vr\text{.}\)
(b)
Let \(C_2\) be the line segment from \((-2,5)\) to \((3,30)\text{.}\) Calculate \(\int_{C_2}\vF\cdot d\vr\text{.}\)
(c)
Let \(C_3\) be the circle of radius \(3\) centered at the origin, oriented counterclockwise. Calculate \(\oint_{C_3} \vF\cdot d\vr\text{.}\)
(d)
To connect the previous parts of this activity, use a graphing utility to plot the curves \(C_1\) and \(C_2\) on the same axes.
(i)
What type of curve is \(C_1 - C_2\text{?}\)
(ii)
What is the value of \(\oint_{C_1-C_2}\vF\cdot d\vr\text{?}\)
(iii)
What does your answer to part c allow you to say about the value of the line integral of \(\vF\) along the top half of \(C_3\) compared to the line integral of \(\vF\) from \((3,0)\) to \((-3,0)\) along the bottom half of the circle of radius \(3\) centered at the origin?