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# C1 - Differentiation question watch

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1. Hi

Wonder if anyone can offer help with this.

y=x^3/2 + 48/x, x>0

find value of x and y when dy/dx = 0

So i've put the equation so it can be differentiated

y = x^3/2 + 48^x-1

Then differentiated it

dy/dx = 3/2x^1/2 - 48x^-2

Then

0 = 3/2x^1/2 - 48x^-2

And its were to go from here i'm stuck on.

Any help is appreciated. Thanks.
2. Looks good.

Where you're stuck... you've got an equation that you can rearrange to find x. If you poke that about, you'll get the value of x that gives you dy/dx =0. If you plug that value into the original equation, that'll give you y when dy/dx=0.
I hope that makes sense.
3. Yep that makes sence. Quite simple wasn't it really! Thanks
4. No problem =)

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Updated: November 16, 2008
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