How do you find the linearization at a=1 of f(x) = x^4 + 4x^2f(x)=x4+4x2?

1 Answer
Nov 5, 2015

A linearization is a tangent line.

Explanation:

The linearization of f(x) = x^4 + 4x^2f(x)=x4+4x2 at a=1a=1 is one form of the equation of the line tangent to the graph of ff at the point (1,f(1))(1,f(1)).

For f(x) = x^4 + 4x^2f(x)=x4+4x2, we have f(1) = 5f(1)=5 and f'(x) = 4x^3+8x, so f'(1) = 12.

The tangent line has point-slope form:

y-f(1) = f'(1)(x-1) " " " " y-5=12(x-1).

The linearization is:

y=f(1) + f'(1)(x-1) " " " " y=5 + 12(x-1).