# 1 or y

1. ### Expectation of 1/Y for Uniform

Hi, I need to find the expection of 1/Y where Y is distributed by UNIF(1,2). Can I do a jacobian transformation to find the pdf of 1/Y and then \int(1/Y)f_{1/Y}(Y) with limits 1 and 2? Help much appreciated
2. ### X, Y, Z are coprime integers. 1/x + 1/y = 1/z. Prove that (X+Y) is a square number.

Okay, so I'm stuck on this for an hour now, so I'd really appreciate some help, please: X, Y, Z are coprime integers. We also know that 1/x + 1/y = 1/z. Prove that (X+Y) is a square number. ----- This should be entry level university math, but I'm stuck with it. I hope I posted to the right...
3. ### In the expression, 1/(y+6), why can't y equal 0,3,-6, or -3?

I understand that y can't equal -6 because it will make the denominator 0, but why the other numbers?
4. ### Find integer solutions to 1/x + 1/y = 1/14

Find all solutions where x and y are integers: \frac{1}{x} + \frac{1}{y} = \frac{1}{14} this can be rearranged to: \frac{xy}{x + y} = 14 I know how to solve diophantine equations of the form ax + by = c Obviously the given equation is in a different form. How do I solve?
5. ### Given x+(1/y)= y + (1/z) = z+ (1/x). Prove x=y=z.

This is a simple math problem. I do remember solving these in grade 9. forgot all the formulas so don't even know where to start. x+(1/y)= y + (1/z) = z+ (1/x) Prove x=y=z This is kind of urgent. Millions of thanks in advance
6. ### integrate f(x,y) = 1/y over R, where R is the region 0 < x < y, 0 <y < 1, x + y > .5

Tried using y=0..1/4, x=1/2-y..1 and y=1/4..1, x=y..1 as integration limits and also tried the reverse order but there is always problem with integrating 1/y up to the x axis. Any help please? Thanks.
7. ### Effect of y² and 1/y on oblique asymptotes

Hi everyone. If I have a y= graph and I do a transformation of either 1/y or y², the oblique asymptotes will disappear as they are no longer 'oblique'. Is that correct. A simple yes or no would suffice. Enjoy your day. Thanks.
8. ### derivative of 1/y

ok so i have the problem: If and , find by implicit differentiation. so i differentiate both sides and get -1/x^2 + -y'/y^2 = 0 then i solve for y' and get y'=-y^2/x^2 this is wrong but i do not know where i went wrong..... im thinking it has to do with the derivative of the 1/y. could i...
9. ### cosec(cos^-1 (1/y)

Can someone please check this for me thanks. Question is \cos ec(\cos ^{ - 1} (\frac{1}{y})) = This is what I worked it to be \begin{array}{l} {\rm let }\theta = \cos ^{ - 1} (\frac{1}{y}) \\ \cos \theta = \frac{1}{y} \\ \cos ^2 \theta + \sin ^2 \theta = 1 \\ (\frac{1}{y})^2 +...
10. ### 1/x - 1/y = 1/2005

Find all pairs of positive integers x and y that safisfy the equation: 1/x - 1/y = 1/2005