Curves: gradient: the quadratic curve y = x²+x+2 Move the slider to move the red line. The gradient of the quadratic curve y = x²+x+2 changes as you move along the curve, so it does not have any one fixed value. But you can find the gradient at a point on the curve by drawing a straight line that just touches the curve at that point. This line is called a tangent line and is shown above in red. The gradient of this line tells you the gradient of the curve at the point selected. controls