I see that you have but what do you mean by "c1= x(1- x)", "c2= 4x(1-x)"? Do you mean that the curve is given by the parametric equations (x, y)= (t(1-t), 4t(1-t))? I have changed the parameter in the definition of the curve to t so as not to confuse it with the "x" in the vector function. The integral of a vector function on a curve is where is the tangent differential to the curve.

Here, if the curve really is , then .

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You will need to put , into that so that you have an integral in t only.