The gradient of a curve at any point \((x, y)\) is \(6 x^{2}-6 x+\) 11. If the curve passes through the point \((0,3)\), find the equation of the curve.
A. \(2 x^{3}-3 x^{2}+11 x+3\) B. \(3 x^{3}+2 x^{2}-11 x+3\) C. \(2 x^{3}-3 x^{2}+11 x-3\) D. \(3 x^{3}-2 x^{2}+11 x-3\)
Correct Answer: A
Explanation
Given gradient \(\frac{d y}{d x}=6 x^{2}-6 x+11\) If we cross - multiply, we have \(d y=\left(6 x^{2}-6 x+11\right) d x\) Integrating both sides \begin{array}{l} \int d y=\int\left(6 x^{2}-6 x+11\right) d x \\ y=\frac{6 x^{3}}{3}-\frac{6 x^{2}}{2}+11 x+k \end{array} \(y=2 x^{3}-3 x^{2}+11 x+k\) To find the constant \(k\), we substitute the point \((0.3)\) i.e. \(x=0, y=3\) \(3-2(0)^{3}-3(0)^{2}+11(0)+k\) \(3=k\) or \(k=3\) \(\therefore y=2 x^{2}-3 x^{2}+11 x+3\)