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lovesit2x
Group Title
Find dx/dy for the following function:
y=sinx+5e^.4x
dx/dy =
 one year ago
 one year ago
lovesit2x Group Title
Find dx/dy for the following function: y=sinx+5e^.4x dx/dy =
 one year ago
 one year ago

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lovesit2x Group TitleBest ResponseYou've already chosen the best response.0
what does dx/dy equals
 one year ago

Hoa Group TitleBest ResponseYou've already chosen the best response.0
I just want to make sure the question, because dx/ dy !=dy/dx
 one year ago

Hoa Group TitleBest ResponseYou've already chosen the best response.0
if it is dx/ dy. it's not easy to solve. you must solve for x first , then take derivative respect to y.
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
it will behave implicitly
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
i think she means dy/dx
 one year ago

lovesit2x Group TitleBest ResponseYou've already chosen the best response.0
i thought i had to find the derivative and then solve for y
 one year ago

Hoa Group TitleBest ResponseYou've already chosen the best response.0
@mathsmind you help her, ok?
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
no u help her
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
can u double check the question plz
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
it must be dy/dx at ur level
 one year ago

lovesit2x Group TitleBest ResponseYou've already chosen the best response.0
\[Find \frac{ dx }{ dy } for the following function. Y = sinx + 5e ^{0.4x}\]
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
u allowed everyone to escape from this question hehehehe
 one year ago

lovesit2x Group TitleBest ResponseYou've already chosen the best response.0
lol i know, i wish i could escape it too
 one year ago

Xavier Group TitleBest ResponseYou've already chosen the best response.1
dx/dy = 1/(dy/dx)
 one year ago

lovesit2x Group TitleBest ResponseYou've already chosen the best response.0
@jim_thompson5910 rescue me please
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
ok i will solve it all it is implicit differentiation but in terms of x
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
so when u diff sin(x) it will be cos(x)dx/dy
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
and y will become 1 when u differentiate it
 one year ago

Xavier Group TitleBest ResponseYou've already chosen the best response.1
Just find dy/dx and take the reciprocal.
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
nope don't do that
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
they are not the same
 one year ago

Xavier Group TitleBest ResponseYou've already chosen the best response.1
Look, dx/dy = 1/(dy/dx)
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
no it does not work like that
 one year ago

Xavier Group TitleBest ResponseYou've already chosen the best response.1
I hope you're kidding. I'm not manipulating fractions
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
look multiply both sides
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
u r missing the chain rule this is calculus not algebra
 one year ago

Xavier Group TitleBest ResponseYou've already chosen the best response.1
http://math.stackexchange.com/questions/292590/isdxdy1dydxincalculus
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
the case where u use a reciprocal is by using the chain rule and cancelling each term out
 one year ago

Azteck Group TitleBest ResponseYou've already chosen the best response.0
Can't you implicit differentiate in this situation?
 one year ago

Azteck Group TitleBest ResponseYou've already chosen the best response.0
implicitly*
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
yes that is different from ur fomula
 one year ago

lovesit2x Group TitleBest ResponseYou've already chosen the best response.0
im even more confused...
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
he wants u to use L rule
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
which is similar to what i said about the chain rule
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
Lebenz derived a formula from the chain rule
 one year ago

Azteck Group TitleBest ResponseYou've already chosen the best response.0
\[\large y=\sin x+5e^{0.4x}\] \[\large 1=(\cos x +2e^{0.4x})\frac{dx}{dy}\]
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
nope i told u don't do that, unless if u want to apply Lebenz rule u need to take the inverse of the function then take the reciprocal ...
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
because calculus is about functions and expansions
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
read that carefully If the derivative of y = f(x) is dy/dx, then the derivative of the inverse function which expresses x in terms of y is given by the formula
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
in other words ur Lebenz works if x= sin(y)+5e^y
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
so u can take the inverse of the function then apply the rule ok
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
i told u they are not the same but thanks anyway for bribing the topic up
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
so take the inverse of the function then use the rule
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
or solve it implicitly as i started
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
if the case was simple like this then implicit differentiation would have never exist
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
\[y = \sin(x) + e^{0.4x} \longrightarrow 1=\frac{dx}{dy}\cos(x)+2\frac{dx}{dy}e^{0.4x}\]
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
the method u use is solving this in an implicit way
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
take dx/dy as a common factor
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
well @Xavier ur method also works congratulation!
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
so both methods work fine, actually u made me come with a new theory in math, or a different proof for Leben'z formula. although maths is not my major, but i will write a new paper on this and publish it
 one year ago

mathsmind Group TitleBest ResponseYou've already chosen the best response.0
not just that i will change my proof for Kepler's laws of motion ...
 one year ago
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