Can I get help on these Three questions. Thank you.

3. [0/1 Points] DETAILS PREVIOUS ANSWERS SCALCET8 15.4.011. MY NOTES PRACTICE ANOTHER A lamina occupies the part of the disk x2 + y2 S 25 in the first quadrant. Find its center of mass if the density at any point is proportional to its distance from the x-axis. _ _ _ 1875 18751: (X'y)'( 1000' 1250 ) X 4. [l1 Points] DETAILS SCALCET8 15.4.013. MY NOTES PRACTICE ANOTHER The boundary of a lamina consists of the semicircles y = 1 x2 and y = 1/ 4 x2 together with the portions of the Xaxis that join them. Find the center of mass of the lamina if the density at any point is proportional to its distance from the origin.Hint: use polar coordinates (E, 7/) =( ) Suppose X and Y are random variables with joint density function. _ -(0-5X + 0-D) ifx 2 D, 2 0 f(x, y) = 0 19 - y 0 otherWIse (a) Is fa joint density function? (9 Yes O No V (b) Find P(Y 2 7). (Round your answer to four decimal places.) 5.7311 3' Find P(X S 5, Y S 3). (Round your answer to four decimal places.) (c) Find the expected value of X. Find the expected value of Y