The Purplemath Forums

Given the function: f(x)=x 4 -8 2 +7 1. At what point(s), if any, are the tangents to the graph of f(x) horizontal? So I found the derivative of f(x) and set it to zero... 0=4x 3 -16x 0=4x(x 2 -4) 0=4x(x+2)(x-2) and then set the three parts of the equation equal to zero to find the x values.. 0=4x -...