(New question) C4 Differentials

Any help would be appreciated

the RHS is $e^{x-y}$ which can be written as $\dfrac{e^x}{e^y}$ so you have:

$\dfrac{dy}{dx} = \dfrac{e^x}{e^y}$

You should see your mistake now, which is in the third line of your working.

Which equates to what I put in the fourth line of my working..?

as $\dfrac{1}{\frac{1}{e^{y}}} = e^{y}$

Which equates to what I put in the fourth line of my working..?

as $\dfrac{1}{\frac{1}{e^{y}}} = e^{y}$

Your working is fine, but it wants you to find y so at the end you just need to take the natural log of both sides .

Sorry again.

New question attached^

glancing at it, It looks like you want something like

$\displaystyle \frac{dA}{dt}=kA$ where $A$ is the area of weed and $t$ is the time in days... and then use $\displaystyle \frac{1}{\frac{dA}{dt}}=\frac{dt}{dA}$ to integrate your differential equation.

Then use the given conditions to find simultaneous equations to find k and the constant of integration.