Example 4.8. evaluate () r dr de, over the area included between the circles r=2 sine and r = 4 sin 0. (irsin6 r sin 6 dr d0, over the area of the cardioid r =

Example 4.8. Evaluate () r dr de, over the area included between the circles r=2 sine and r = 4 sin 0. (irsin6 r sin 6 dr d0, over the area of the cardioid r = a (1 + cos 0) above the initial line.