2cd derivative

[ffuh205]

Give the value of the second derivative for the function g(x) = (x^2+4)^3 at x = 1/5. For the second derivative I got(6·(x^2 + 4)·(5·x^2 + 4)) and plugging in 1/5 I got 97.455. but was marked incorrect. What am I doing wrong?

 

[Deleted member 4993]

Give the value of the second derivative for the function g(x) = (x^2+4)^3 at x = 1/5. For the second derivative I got(6·(x^2 + 4)·(5·x^2 + 4)) and plugging in 1/5 I got 97.455. but was marked incorrect. What am I doing wrong?

g'(x) = 3*(2x)*(x[sup:no25fc7r]2[/sup:no25fc7r] + 4)[sup:no25fc7r]2[/sup:no25fc7r] = 6x * (x[sup:no25fc7r]2[/sup:no25fc7r] + 4) [sup:no25fc7r]2[/sup:no25fc7r]

g"(x) =6[(x[sup:no25fc7r]2[/sup:no25fc7r] + 4)[sup:no25fc7r]2[/sup:no25fc7r] + 4x[sup:no25fc7r]2[/sup:no25fc7r](x[sup:no25fc7r]2[/sup:no25fc7r] + 4)] = 6(x[sup:no25fc7r]2[/sup:no25fc7r] + 4) * [(x[sup:no25fc7r]2[/sup:no25fc7r] + 4) + 4x[sup:no25fc7r]2[/sup:no25fc7r]] = 6(x[sup:no25fc7r]2[/sup:no25fc7r] + 4) * (5x[sup:no25fc7r]2[/sup:no25fc7r] + 4)

g"(1/5) = 101.808

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