1. ## suppose..

yea i don't even know where to start on this problem...

Suppose and . Find when .

(dx/dt)=?

2. Originally Posted by tbenne3
yea i don't even know where to start on this problem...

Suppose and . Find when .

(dx/dt)=?
$\displaystyle \frac{d}{dt}\left(xy = 3\right)$

$\displaystyle x \cdot \frac{dy}{dt} + y \cdot \frac{dx}{dt} = 0$

take it from here?

3. Originally Posted by skeeter
$\displaystyle \frac{d}{dt}\left(xy = 3\right)$

$\displaystyle x \cdot \frac{dy}{dt} + y \cdot \frac{dx}{dt} = 0$

take it from here?
is it -3?

4. $\displaystyle \frac{dx}{dt}=\frac{dx}{dy}\frac{dy}{dt}$

5. Originally Posted by tbenne3
this is not that difficult.

$\displaystyle xy = 3$

if $\displaystyle x = -3$ , then $\displaystyle -3y = 3$ ... $\displaystyle y = -1$

you were given $\displaystyle \frac{dy}{dt} = -3$ ... now use the derivative equation to solve for $\displaystyle \frac{dx}{dt}$

6. Originally Posted by skeeter
this is not that difficult.

$\displaystyle xy = 3$

if $\displaystyle x = -3$ , then $\displaystyle -3y = 3$ ... $\displaystyle y = -1$

you were given $\displaystyle \frac{dy}{dt} = -3$ ... now use the derivative equation to solve for $\displaystyle \frac{dx}{dt}$
sorry just not following.. what is the derivative of dx/dt

7. $\displaystyle x \cdot \frac{dy}{dt} + y \cdot \frac{dx}{dt} = 0$

$\displaystyle (-3) \cdot (-3) + (-1) \cdot \frac{dx}{dt} = 0$

solve for the value of $\displaystyle \frac{dx}{dt}$

8. Originally Posted by skeeter
$\displaystyle x \cdot \frac{dy}{dt} + y \cdot \frac{dx}{dt} = 0$

$\displaystyle (-3) \cdot (-3) + (-1) \cdot \frac{dx}{dt} = 0$

solve for the value of $\displaystyle \frac{dx}{dt}$
thanks