Question

Which of the following is an equation of the line tangent to the graph of f(x)=x^4+2x^2 at the point where f'(x)=1 ?
A) y= 8x-5
B)y=x+7
C) y=x+0.763
D) y=x-0.122
E)y=x-2.146

Answer 1

since f'(x) = 1 thats the slope of the line, so A is out by default

next thing to do is to determine at which point f'(x) = 1 by taking the derivative of f(x) and solving it.