Polar differential problem with my workings...

Hi All,

I'm having problems with this question and need someone to look at my workings and give a gentle push in the right direction. If anyone can help I'd be most grateful.

Calculate for the curve whose equation in polar coordinates is

So my understanding is that polar coords are given as so not quite sure what to do with this. Would I rearrange to find such that and keep r as it is????

Or is it using r and with &

Then find and hence and and finally get the result

Best regards, Felix

Re: Polar differential problem with my workings...

Quote:

Originally Posted by

**FelixHelix** Hi All,

I'm having problems with this question and need someone to look at my workings and give a gentle push in the right direction. If anyone can help I'd be most grateful.

Calculate

for the curve whose equation in polar coordinates is

So my understanding is that polar coords are given as

so not quite sure what to do with this. Would I rearrange to find

such that

and keep r as it is????

Or is it using r and

with

&

Then find

and hence

and

and finally get the result

Best regards, Felix

Note that in this case.

Re: Polar differential problem with my workings...

I'm not sure what you have done here. Can you expalin? Also I'm guessing that that is a typo on your second line and should read ...

Re: Polar differential problem with my workings...

Quote:

Originally Posted by

**FelixHelix** I'm not sure what you have done here. Can you expalin? Also I'm guessing that that is a typo on your second line and should read

...

Sorry about the typo.

I have merely used the product rule to differentiate and .

Re: Polar differential problem with my workings...

Quote:

Originally Posted by

**FelixHelix** Hi All,

I'm having problems with this question and need someone to look at my workings and give a gentle push in the right direction. If anyone can help I'd be most grateful.

Calculate

for the curve whose equation in polar coordinates is

So my understanding is that polar coords are given as

so not quite sure what to do with this. Would I rearrange to find

such that

and keep r as it is????

Or is it using r and

with

&

Then find

and hence

and

and finally get the result

Best regards, Felix

You should know that .

So