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?

Answer 1

have you tried taking the derivative of your function and seeing where y =1?

Answer 2

that will give me some weird numbers.I got x=1/16

Answer 3

\[4x^3+4x=1 \]
this is what got you 1/16? for x

Answer 4

i personally. would just graph the derivative and go to table and see where y =1

Answer 5

Didn't think of that, xD ty

Answer 6

did it work?

Answer 7

Wait no I don't think it does work

Answer 8

what part in calc are you in? are you still doing the limit definition?

Answer 9

I belive I am past limits, currently I'm doing derivatives,concavity,etc

Answer 10

im talking about the limit definition for derivatives. i remember taking derivatives using the limit definition where x= some number. then having to plug a function into F(x+deltax)-f(x)/deltax.

Answer 11

but other than the way i explained it a sec a go without knowing the context of the problem. looks to be the way i would do it. lemme check my calc book real fast see if i see something

Answer 12

Appreciate the help, but in all honesty I have no idea and I can't find it in my calculus book.

Answer 13

this is a very simple problem, were just over looking something @nincompoop he will enlighten us

Answer 14

@sourwing you mind enlightening us.

Answer 15

A solution using Mathematica 9 Home Edition is attached.

Answer 16

first, take the derivative of the function
then equate it to 1

Answer 17

that was my first bit of advice. i guess it didnt work for him or something?