- #1
physphys
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Homework Statement
At what points on the curve y = (x^2)/(2x+5) is the tangent line horizontal?
Homework Equations
Quotient rule
The Attempt at a Solution
I figured out the derivative which is
2x(2x+5) - 2x^2
-----------------
(2x+5)^2
I also know that for the equation of the tangent to be horizontal, it needs to have a slope of 0, so y' = 0
Therefore I tried to do 2x(2x+5) - 2x^2 = 0, and I got 2x^2 + 10x = 0 which means that x must be -5. However when I put it into the calculator, it doesn't agree with me, so I went wrong somewhere.
Thanks in advance!