### Home > CALC > Chapter 7 > Lesson 7.4.1 > Problem 7-177

7-177.

Given:

*f*(*x*) = 5*x*^{4}− 3*x*^{2 }Homework Help ✎Write the equation of the tangent line to

*f*(*x*) at*x*= 1.Use your tangent line to approximate

*f*(1.1).Is the approximation an over or under estimate of the actual value?

Use point-slope form of a line. *f*(1) will give you the point, and *f* '(1) will give you the slope.

Since a linear equation is easier to evaluate than a 4th-degree polynomial, use the tangent line to approximate *f*(1.1).

Is the graph of *y* = *f*(*x*) concave up or down *x* = 1?