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wantedcriminal03
09-29-2008, 05:07 PM
How do I make the c the subject of:

Q= sqrt((c+d)/(c-d))

I did Q^2= (c+d)/(c-d)
= (c+d)^2/(c^2-d^2)

and couldn't get any further...

Denis
09-29-2008, 05:21 PM
I did Q^2= (c+d)/(c-d)
= (c+d)^2/(c^2-d^2)

NO!
Next step should be: Q^2(c - d) = c + d ; carry on...

wantedcriminal03
09-29-2008, 05:29 PM
I tried that way aswell but I I got to c= Q^2 c - Q^2 d -d :?

Denis
09-29-2008, 08:47 PM
HOW d'heck did you arrive at that ? :shock:

Q^2(c - d) = c + d

cQ^2 - dQ^2 = c + d

cQ^2 - c = dQ^2 + d

c(Q^2 - 1) = d(Q^2 + 1)

c = d(Q^2 + 1) / (Q^2 - 1)