Find equation of tangent line given only x. Please help!
View Single Post
Feb13-12, 12:21 AM
I'm assuming that the equation is y = (x^3 - 4x + 2)(x^4 + 3x - 5)
If y = f(x) * g(x), dy/dx [itex]\neq[/itex] f'(x) * g'(x), which is what you seem to be doing here. You should be thinking "product rule."
Sorry, yes you are right about the equation. And regarding the product rule yes, you are also right!
So, when I find it using the product rule, I insert the -1, and then that gives me the slope?