sdfgw
|
  |
 |
| Joined: 08 Jan 2009 |
| Total Posts: 41681 |
|
|
| 17 Oct 2011 10:24 AM |
i know this isn't strictly scripting
but
we always allow mathsy threads here
and for some reason i'm struggling to make it the right thingy |
|
|
| Report Abuse |
|
|
sncplay42
|
  |
| Joined: 27 Nov 2008 |
| Total Posts: 11891 |
|
|
| 17 Oct 2011 11:18 AM |
y=1/x=x^-1 dy/dx=-x^-2=-1/(x^2) |
|
|
| Report Abuse |
|
|
sncplay42
|
  |
| Joined: 27 Nov 2008 |
| Total Posts: 11891 |
|
|
| 17 Oct 2011 11:20 AM |
"from first principles"
I need to pay more attention |
|
|
| Report Abuse |
|
|
sdfgw
|
  |
 |
| Joined: 08 Jan 2009 |
| Total Posts: 41681 |
|
|
| 17 Oct 2011 11:23 AM |
snc
you have no idea how much I expected someone to miss that part
i probably should've emphasised it more |
|
|
| Report Abuse |
|
|
sncplay42
|
  |
| Joined: 27 Nov 2008 |
| Total Posts: 11891 |
|
|
| 17 Oct 2011 11:27 AM |
Here's what I got:
dy/dx = lim(h->0) (1/(x+h)-1/x)/h =lim(h->0) ((x-(x+h))/x(x+h))/h =lim(h->0) -h/xh(x+h) =lim(h->0) -1/x(x+h) =lim(h->0) -1/(x^2+hx) =-1/(x^2+0) =-1/x^2 |
|
|
| Report Abuse |
|
|
sdfgw
|
  |
 |
| Joined: 08 Jan 2009 |
| Total Posts: 41681 |
|
|
| 17 Oct 2011 11:29 AM |
oh tf
I forgot to multiply the dominator by x(x+h)
well that'll explain my failure then |
|
|
| Report Abuse |
|
|
Friaza
|
  |
| Joined: 26 Dec 2008 |
| Total Posts: 6229 |
|
|
| 17 Oct 2011 11:51 AM |
| This thread makes smart people feel stupid :( |
|
|
| Report Abuse |
|
|