Differentiation problem, please help!
Yes
Suppose \[\sqrt{x}+\sqrt{y}=1\]. Find y''
I found f' already, which I got \[\frac{ -\sqrt{y} }{ \sqrt{x} }\] for, is that right so far?
Yes But Hold On Im Working It
Yes. You are right @stottrupbailey
Thank you :) So I'm confused about the next step though
What do you have to do next?
quotient rule, right?
yes. do you have to find f''?
yes
Did you try?
yes, this is what I have so far\[\frac{ \frac{ -\sqrt{x} }{ 2\sqrt{y} }\frac{ dy }{ dx } +\frac{ \sqrt{y} }{ 2\sqrt{x} } }{ x }\]
I'm just confused about getting dy/dx by itself because this isn't an equation, so I can't subtract and multiply stuff over.
substitute \[\frac{dy}{dx}=-\frac{\sqrt y}{\sqrt x}\]
Oh, I see, okay just a sec
so is the answer \[\frac{ \sqrt{x}+\sqrt{y} }{ 2x \sqrt{x} }\] ?
I get this finally \[\frac{ d^{2}y }{ dx^{2}}=\frac{ -x^{\frac{ -3 }{ 2 }}-2x^{\frac{ -1 }{ 2 }} }{ y^{\frac{ -3 }{ 2 }} }\]
@stottrupbailey yes you are right
Thanks so much ash2326! :)
you're welcome :D
Join our real-time social learning platform and learn together with your friends!