Question

1/p + 1/q = 1/f. How do you solve for f?

Answer 1

\[ f = \frac{1}{\frac{1}{p}+\frac{1}{q}} = \frac{pq}{p+q} \]

Answer 2

How do you get there?

Answer 3

Just take the reciprocal on both sides.

Answer 4

I still don't understsand the steps.. I'm very new to this.

Answer 5

1/p + 1/q = (p + q)/pq. Hence if 1/f = 1/p + 1/q, that means
1/f = (p + q)/pq.
Taking the reciprocal of both sides, f = pq/(p + q).