# Thread: double integral to find area

1. ## double integral to find area

find ∫ y dA , where R is the region between (y^2) + (x-2)^2 = 4 and y = x in the first quadrant

i have skteched out the diagram and did it,. But my ans is 13/ 3 rather than 4/3 , is the ans provided wrong ? P/s : ans provided is 4/3 ...

2. ## Re: double integral to find area

Hey xl5899.

You might want to check your limit for the A2 part - it should be 4 - (x+2)^2 not 4 - x + 2.

See if you can adjust the limits and make sure they correspond to the A2 part [draw a diagram and post it if you need to] before re-trying the evaluation of the integral.

3. ## Re: double integral to find area

There are two regions "between $\displaystyle (x- 2)^2+ y^2= 4$ and y= x", one above y= x and one below. Which do you mean?

4. ## Re: double integral to find area

Originally Posted by chiro
Hey xl5899.

You might want to check your limit for the A2 part - it should be 4 - (x+2)^2 not 4 - x + 2.

See if you can adjust the limits and make sure they correspond to the A2 part [draw a diagram and post it if you need to] before re-trying the evaluation of the integral.
well , after correction , my A2 = 8/3 , so A 1= 4/3 , A1 + A2 = 4 , which is still not 4/3 , which part is wrong ?