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**The tangent at a point P on the curve y = x^3 intersects the curve again at a point Q. Show that the slope of the tangent at Q is four times the slope of the tangent at P.**

**y=x^3, dy/dx=3x^2, y=mx+b**

I tried setting the derivative equal to the original function to see when they intersect and go from there but then realized that the tangent at a certain point is not the same as the equation for the slope of the tangent at -any- point. I looked at this thread https://www.physicsforums.com/showthread.php?t=94520 but still could quite figure it out, I wasn't sure whether to post in a 5 year old thread or make a new one so feel free to move me if I made the wrong choice. If someone could get me started that would be great.