Tangent Line Calculator
The tangent line touches a curve at a single point and has the same slope as the curve there. This calculator evaluates f(a) for the point of tangency, estimates the slope f'(a) numerically, and assembles the tangent line in point-slope and slope-intercept forms.
Frequently asked questions
How is the slope of the tangent found?
The slope is the derivative f'(a), estimated with a central-difference approximation.
What forms of the line are returned?
Both the point-slope form y − f(a) = f'(a)(x − a) and the slope-intercept form y = mx + b.
What if the function is undefined at the point?
If f(a) cannot be evaluated, the calculator reports that there is no tangent line at that point.