derivatives - math problem help

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redlotus

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find the derivative of:

f(x)=ln(x+5)^(1/2)

wtf

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1/2(x+5) shud be the answer... (however, please confirm yourself)

dlnx/dx = 1/x, so use chain rule as shown below,

dln(sqrt(x+5)) d(sqrt(x+5))

__________ * ___________

d(sqrt(x+5)) dx

wtf

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in fact, i shuda been clearer.... 1/ (2(x+5)) <--- answer

Namaskaar

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I think it should be (just thinking, but I would have this answer if I were asked)
1/2(x+5)^-1/2

I haven't taken much of calculus and my familiarity with it is from my 11th grade where I passed maths by securing 36 in final exam :) So, don't rely on it completely, though i believe in my solution to my knowledge, better check it by urself.

sports freak

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i think WTF is correct.. i got the same answer..

Namaskaar

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Hey redlotus, when u find out correct solution, will you report it here.

because as far as I know
d ln(x+5)^1/2 / dx = 1/2 (x+5)^1-1/2

= .5(x+5)^-1/2

sports freak

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hey namaskar , u better take some derivative classes!! i think u know nothing abt calculus and esp derivative....

Namaskaar

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Sports freak, I'm happy that I don't need to. Days of school overrrrrrrrrr for now. Thanx for pointing out anyway.

Ya I find something wrong with my solution

If the derivative was with respect to (x+5) i think my earlier solution would be right.

d ln(x+5)^1/2 / d (x+5) = .5 (x+5)^{- .5}

but with respect to x only nooooooo.
Sorry for giving wrong solution. My baddddddddd :)

Namaskaar

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let me guess another soln

how about 2(sqrt X)

Pls someone post a real soln.
I am getting curious :)
and it is boring that all other threads today in Sajha are related to dead person.

raju161

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$d/dx(f(x) = sqrt(log(x+5))) = (f\'(x) = 1/(2 (x+5) sqrt(log(x+5))))$

$Possible derivation:\nd/dx(f(x)) = d/dx(sqrt(log(x+5)))\n | The derivative of f(x) is f\'(x):\n= | f\'(x) = d/dx(sqrt(log(x+5)))\n | Use the chain rule, d/dx(sqrt(log(x+5))) = ( dsqrt(u))/( du) ( du)/( dx), where u = log(x+5) and ( dsqrt(u))/( du) = 1/(2 sqrt(u)):\n= | f\'(x) = (d/dx(log(x+5)))/(2 sqrt(log(x+5)))\n | Use the chain rule, d/dx(log(x+5)) = ( dlog(u))/( du) ( du)/( dx), where u = x+5 and ( dlog(u))/( du) = 1/u:\n= | f\'(x) = (d/dx(x+5))/(2 (x+5) sqrt(log(x+5)))\n | Differentiate the sum term by term:\n= | f\'(x) = (d/dx(5)+d/dx(x))/(2 (x+5) sqrt(log(x+5)))\n | The derivative of 5 is zero:\n= | f\'(x) = (d/dx(x))/(2 (x+5) sqrt(log(x+5)))\n | The derivative of x is 1:\n= | f\'(x) = 1/(2 (x+5) sqrt(log(x+5)))$