`f(x) = x^2 + 2x - 1, (1, 2)` Find an equation of the tangent line to the graph of f at the given point.

1 Answer

hkj1385's profile pic

hkj1385 | (Level 1) Assistant Educator

Posted on

The given function is:-

f(x) = (x^2) + 2x

differentiating both sides w.r.t 'x' we get

f'(x) = 2x + 2

Now, slope of the tangent at the point (1,2) = f'(1) = (2*1) + 2 = 4

Thus, equation of the tangent at the point (1,2) and having slope = 4 is :-

y - 2 = 4*(x - 1)

or, y - 2 = 4x - 4

or, y - 4x + 2 = 0 is the equation of the tangent to the  given curve at (1,2)