The equation of a curve is $\displaystyle y=2x^2-kx+3$, where k is a constant.

a) Find in terms of k, the gradient of the tangent at point A where x=1.

b) Given that the tangent at point A passes through the point B(5,1), find the value of k.

Attempt

a) $\displaystyle \frac{dy}{dx}= 4x-k$