Finding the double integral using polar coordinates.

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enter image description here

Above is the graph I have obtained from the equation.

Hi there so I've just been introduced to using polar co-ordinates to find double integrals and Im having a hard time working out how to tackle questions step by step.

Im currently looking at the question:

$I_{6}=\int\int_{Q}x/\pi (x^{2}+y^{2}) dxdy$ with $Q=\{(x,y)|(x-3/2)^2 +y^2 \leq9/4, y\geq0\}$

And Im struggling to make a start to this as I dont know how to obtain the limits of the double integral from $Q$ .

All I know is that I should eventually obtain the answer 3/4.

Any help would be greately appreciated.

Update:

So I now have the double integral

$\int_{0}^{\pi/2}\int_{0}^{3cos\theta}(rcos\theta/\pi)*((rcos\theta)^{2}+(rsin\theta)^{2}) rdrd\theta$

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On your specific question about how the equation in polar form becomes $r = 3 \cos \theta$,

In polar form, $x = r \cos \theta, y = r \sin \theta$

Now your curve is $(x-3/2)^2 +y^2 = 9/4 \implies x^2 + y^2 = 3x$

$r^2 cos^2 \theta + r^2 \sin^2 \theta = 3r \cos \theta$

$r^2 = 3r \cos \theta \implies r = 3 \cos \theta$

Here is a diagram showing how $r$ changes with $\theta$ with $x$-axis.

enter image description here