Given: f(x) = 5x4 − 3x2 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?