1/p + 1/q = 1/f How do I solve for q?
C cmdrox New member Joined Oct 16, 2007 Messages 3 Oct 16, 2007 #1 1/p + 1/q = 1/f How do I solve for q?
I ilaggoodly New member Joined Oct 4, 2007 Messages 35 Oct 16, 2007 #2 subtract and invert? 1/q = 1/f - 1/p so q = (1/f-1/p)^-1
M Mrspi Senior Member Joined Dec 17, 2005 Messages 2,128 Oct 16, 2007 #3 cmdrox said: 1/p + 1/q = 1/f How do I solve for q? Click to expand... This might be easier if it had no fractions. So, multiply both sides by the least common denominator for all the fractions, pqf: pqf * (1/p) + pqf * (1/q) = pqf * (1/f) qf + pf = pq Ok...you're supposed to solve for q. Get all terms containing "q" on one side of the equals sign, and everything else on the other side.... I'll let you take it from here. If you still have trouble, repost showing everything you've done to try to solve the problem.
cmdrox said: 1/p + 1/q = 1/f How do I solve for q? Click to expand... This might be easier if it had no fractions. So, multiply both sides by the least common denominator for all the fractions, pqf: pqf * (1/p) + pqf * (1/q) = pqf * (1/f) qf + pf = pq Ok...you're supposed to solve for q. Get all terms containing "q" on one side of the equals sign, and everything else on the other side.... I'll let you take it from here. If you still have trouble, repost showing everything you've done to try to solve the problem.
C cmdrox New member Joined Oct 16, 2007 Messages 3 Oct 16, 2007 #4 Wow, that helps a lot. I understand it now, thanks!
D Denis Senior Member Joined Feb 17, 2004 Messages 1,707 Oct 17, 2007 #5 or you can go this way (my favorite): 1/q = 1/f - 1/p 1/q = (p-f) / (fp) q = fp / (p-f)