i cant solve it! im really lost. i know you find f''(x) (i got 9e^3x +12) but i dont know where to go from there what would i do on my calculator?
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Originally Posted by LexiRae i cant solve it! im really lost. i know you find f''(x) (i got 9e^3x +12) but i dont know where to go from there what would i do on my calculator? A horizontal tangent will have a slope of 0. So set $\displaystyle f'(x)=0$ and solve for $\displaystyle x.$
Last edited by Reckoner; Feb 25th 2009 at 04:58 PM. Reason: Stupid error. Thanks, skeeter
Originally Posted by Reckoner A horizontal tangent will have a slope of 0. So set $\displaystyle f''(x)=0$ and solve for $\displaystyle x.$ set $\displaystyle f'(x) = 0$ rather than $\displaystyle f''$ ? $\displaystyle f(x) = e^{3x} + 6x^2 + 1 $ $\displaystyle f'(x) = 3e^{3x} + 12x = 0$ graph f'(x) and look for the zero. using a calculator ... $\displaystyle x \approx -0.156$
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