- #1
illjazz
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Homework Statement
Find the derivative of the function y = cos(a^3 + x^3).
Homework Equations
- Chain rule
- Power rule
The Attempt at a Solution
This is driving me insane.. so here's what I have.
y = cos(a^3 + x^3)
y' = -sin(a^3 + x^3) * d/dx (a^3 + x^3)
y' = -sin(a^3 + x^3) * (3a^2 + 3x^2
y' = -(3a^2)(sin(a^3 + x^3)) - (3x^2)(sin(a^3 + x^3))
I would like to think that that's where this ends.. but my book claims the result is
y' = -(3x^2)(sin(a^3 + x^3))
How? Where the heck does that entire -(3a^2)(sin(a^3 + x^3)) term go!?
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