DLS
Please find the derivative c:
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DLS
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\[y=(3x^2+6x+5)^{(7/2)} \]
cwrw238
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use the chain rule
ley u = 3x^2 + 6x + 5 , then y = u^(7/2)
find du/dx and dy/du
then dy/dx = dy/du * du/dx
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I did the same.
cwrw238
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ok - and what did you get?
cwrw238
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7/2(3x^2 + 6x + 5)^(5/2) * (6x +6)
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Im little confused..
Will it be like this?
\[y=\frac{(3x^{2}+6x+5)^{7/2}}{d(6x+5)} \times \frac{d(6x+5)}{d5} \]
something like this?
perhaps confused..
cwrw238
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y = u^(7/2)
dy/du = (7/2) u^(7/2 - 1) = (7/2) u^(5/2)
substituting back for u dy/du = (7/2) ( 3x^2 + 6x + 5)^(5/2)
du/dx = 6x + 6
now multiply the two results together gives
(7/2)(6x+6)(3x^2 + 6x + 5)^(5/2)
cwrw238
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with practice you won't need to do the substitution u
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how did u get 6x+6
cwrw238
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6x + 6 is the derivative of 3x^2 + 6x + 5 the du/dx in the above post
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thanks!
cwrw238
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you use chain rule when you have a 'function of a function' like this one
3x^2 +6x + 5 is the 'inside' function of (3x^2 +6x + 5)^7/2
cwrw238
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yw
DLS
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i have some more questions im confused with!
cwrw238
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i'm sorry but i must go now
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okay..