Is it the correct change?

Asked May 15 '21 at 05:22

Active May 15 '21 at 06:02

Viewed 36 times

Calculate the integral :

$\displaystyle\iint_D\sqrt{x-y}\;dxdy\;,$

where $\;D=\big\{(x,y)\in\mathbb{R}^2\;\big|\; 1\leq y\leq4\;,\frac{4}{5}x\leq y\leq x\big\}\;.$

My attempt is :

$\displaystyle\int_1^4\int_y^{\frac{5y}{4}}\sqrt{x-y}\;dxdy$

but I did not know if it is correct change .

edited May 15 '21 at 06:02

Angelo

asked May 15 '21 at 05:22

hi hi

Yes it is correct but write the order of integral correctly. Internal integral is $dx$ and outer $dy$. – Math Lover May 15 '21 at 05:32
thanks sir, now im write the correct way – hi hi May 15 '21 at 05:34
answer is $\frac{31}{15}\sqrt 2$ but in the book is $\frac{31}{30}$ which is correct – hi hi May 15 '21 at 05:41
Book answer $\frac{31}{30}$ is correct. You may be making some mistake. – Math Lover May 15 '21 at 05:42
i find the mistake, thanks – hi hi May 15 '21 at 05:45

0 Answers0