Desperate C3 help!!!!!!!!!!!!! HELP!

Year 12s: what will be the first way you research your future options? >>

Scroll to see replies

Reply 40

73337

gorgeousguy

is that rhetorical or do you really not know?

*claps*

Reply 41

gorgeousguy

it means what is x^0.5 when it has been differentiated. basically he wants you to diffgerentiate this! do you know how to do this? i was being sarcastic before after all the step threads but that wasnt directed at you.

Reply 42

calcium878

hi there

what do you mean by the derivative - x^0.5?

Find

\frac{\text{d}}{\text{d}x}\sqrt{x}

0.5x^-0.5

now what?

hi there

now what?

Now put it back into the expression that you got wrong before. And tell us what d/dx e^(x^0.5) is.

Reply 46

DFranklin

hi there

now what?

Now have a look at your answer in post #32 and see if you can work out what's wrong with it, given that

\frac{d}{dx} x^{0.5} = 0.5 x^{-0.5}

Reply 47

hi there

0.5 . x^-0.5 . e^(x^0.5)

is that it?

no. at least not what i worked it iut to be.

Reply 50

hi there

i'm so frustrated. I've given up! What is it?

Reply 51

DFranklin

hi there

0.5 . x^-0.5 . e^(x^0.5)

Looks fine to me.

Reply 52

gorgeousguy

i got it to be: e^(x^0.5) /2(x^0.5)

on seconds thoughts thats the same as what you have writeen just in a different way.

Reply 53

DFranklin

gorgeousguy

i got it to be: e^(x^0.5) /2(x^0.5)

That's the same answer...

Reply 54

gorgeousguy

yes i know sorry. i missed out the 0.5 in the other post - ill now go and stand in the corner and hit myself with the dunce stick

Reply 55

Thaiprawns

gorgeousguy

yes i know sorry. i missed out the 0.5 in the other post - ill now go and stand in the corner and hit myself with the dunce stick

you and me both

Reply 56

gorgeousguy

have you done question 6 yet? just had a look at it and its not to bad. tbh the defferantiation is pretty simple here and if your ok with basicish algebra you shouldnt struggle getting the solution (says me after humiliating myself once tonight!)

Reply 57

hi there

no, i haven't

How do you do it?

Reply 58

calcium878

hi there

no, i haven't

How do you do it?

V = x^2 \sqrt{8-x}

Find dV/dx and equate it to zero to find the values for x at which the maximum (and unrequired minimum) values occur. Then put this value back into the original equation to find the maximum volume.