Question

Given that 1/f = 1/u + 1/v , express u in terms of v and f

Answer 1

u = fv/(v - f)

Explanation:

1/f = 1/u + 1/v

1/u = 1/f - 1/v = v/fv - f/fv = (v-f)/fv

1/u = (v-f)/fv

u = fv/(v - f)