The Maths Prof: Finding Equation of Normal to Curve (Differentiation)
In this lesson I explain how to find the equation of the normal to y = 3x³ + 3x² - 4x + 1 at the point (0,1). Remember, the NORMAL is the line that is PERPENDICULAR to the tangent at that point.
Breakdown of steps:
1. Find gradient of curve (dy/dx=...)
2. Find exact gradient by substituting x coordinate into dy/dx=...
3. Find gradient of normal (remember, the perpendicular gradients multiply to give -1)
4. Using y=mx+c, find c, the y-intercept, by substituting in your gradient value and (x,y) coordinates
5. Bring it all together! :-)
I hope that you find the lesson useful. Subscribe to my YouTube channel to stay up to date with new uploads and follow me on Instagram @themathsprof for more maths!