# total differentiation

• Mar 28th 2010, 10:55 AM
pepsi
total differentiation
i can't see at all how come

(d/dx)(y'/sin^2y)=cosy/siny

i would think that

= [-2(y'^2)cosy/siny]+[y''/sin^2y]

it's frustrating me please give me some help
• Mar 28th 2010, 01:18 PM
skeeter
Quote:

Originally Posted by pepsi
i can't see at all how come

(d/dx)(y'/sin^2y)=cosy/siny

i would think that

= [-2(y'^2)cosy/siny]+[y''/sin^2y]

it's frustrating me please give me some help

is there more to this problem than what you have posted?

... where/how did that first equation come about?
• Mar 28th 2010, 01:24 PM
HallsofIvy
Quote:

Originally Posted by pepsi
i can't see at all how come

(d/dx)(y'/sin^2y)=cosy/siny

i would think that

= [-2(y'^2)cosy/siny]+[y''/sin^2y]

it's frustrating me please give me some help

The second formula is right and the first formula is wrong. It's that simple. Unless, as skeeter has suggested, there is more to the problem.
• Mar 29th 2010, 07:11 AM
pepsi
Quote:

Originally Posted by skeeter
is there more to this problem than what you have posted?

... where/how did that first equation come about?