TANGENT LINE
A line that touches a curve at a point without crossing over. Formally, it is a line which intersects a differentiable curve at a point where the slope of the curve equals the slope of the line.
Equation:
Equation:
NORMAL LINE
A normal line to a point (x,y) on a curve is the line that goes through the point (x,y) and is perpendicular to the tangent line. Since the normal line and tangent line are perpendicular, they will have slopes that are opposite reciprocals of each other. To find the slope of the tangent line at the point (x,y), take the derivative of the function at that point.
Equation:
Equation:
EXAMPLE
Find the equations of the tangent line and normal line.