1. ## unfamiliar polar form

Dear sir,
Would be very glad if someone help me in the below problem.
thanks

2. Do you know the formula for arc length, polar?

$\displaystyle \int_{a}^{b}\sqrt{r^2+\left(\frac{dr}{d\theta}\rig ht)^2}d\theta$

Yes I know the formula which involves theta but limits for 'r' is given , not theta. It is from here I faced difficulty.Please help}

4. Remember that $\displaystyle \frac{dr}{d\theta} = \frac{1}{\frac{d\theta}{dr}}$. I assume you are using $\displaystyle \phi$ to represent $\displaystyle \theta$...

5. Thanks but how we are going to put 'r square' in term of theta and covert the limits of r from 1 to 3 into theta =?
Thanks

6. Dear Sir,
I would appreciate very much if someone would show me the solution to the above question.
Thanks

7. I am unable to see the "attached image" and so have no idea what the problem is.

Thanks

9. Dear Sir,
I would be much obliged if someone can show me the solution of the above problem
thanks