Derivation of graph of v against u

[desmond iking]

Homework Statement

This is the graph of v against u .
i am having problem of getting the shape of graph and getting the point (2f, 2f) . can anyone teach me how to derive it?

Homework Equations

The Attempt at a Solution

sorry. i don't know how to use LATEX. it may be quite untidy if i type it using / sign for all the equation.

so , i have did it beside the graph in the photo . hopefully you guys can understand .

 

[Orodruin]

The question is a bit unclear. Is this the full problem exactly as stated?

It seems you want to find the point where the curves u=v and 1/u + 1/v = 1/f intersect. What happens if you insert the first relation into the second and solve for v?

 

[desmond iking]

The question is a bit unclear. Is this the full problem exactly as stated?

It seems you want to find the point where the curves u=v and 1/u + 1/v = 1/f intersect. What happens if you insert the first relation into the second and solve for v?

this is not a question actually. it's just a note. Can you explain further? i am actually finding v against u in my working. to get the shape of the graph. unfortunealy, i got stucked.

 

[haruspex]

this is not a question actually. it's just a note. Can you explain further? i am actually finding v against u in my working. to get the shape of the graph. unfortunealy, i got stucked.

See if you can get the equation into the form $v - A = \frac B{u-C}$

 

[desmond iking]

thanks , after referring to the old book, i managed to understand it.