Answer :

Certainly! Let's solve the equation [tex]\(\frac{1}{u} + \frac{1}{v} = \frac{1}{f}\)[/tex] for [tex]\(u\)[/tex] step-by-step.

1. Start with the given equation:

[tex]\[ \frac{1}{u} + \frac{1}{v} = \frac{1}{f} \][/tex]

2. Subtract [tex]\(\frac{1}{v}\)[/tex] from both sides of the equation to isolate [tex]\(\frac{1}{u}\)[/tex]:

[tex]\[ \frac{1}{u} = \frac{1}{f} - \frac{1}{v} \][/tex]

3. Find a common denominator for the right-hand side of the equation:

The common denominator for [tex]\(f\)[/tex] and [tex]\(v\)[/tex] is [tex]\(fv\)[/tex]. So, we can rewrite the right-hand side:

[tex]\[ \frac{1}{f} = \frac{v}{fv}, \quad \frac{1}{v} = \frac{f}{fv} \][/tex]

Therefore,

[tex]\[ \frac{1}{u} = \frac{v}{fv} - \frac{f}{fv} = \frac{v - f}{fv} \][/tex]

4. Simplify the right-hand side:

[tex]\[ \frac{1}{u} = \frac{v - f}{fv} \][/tex]

5. Take the reciprocal of both sides to solve for [tex]\(u\)[/tex]:

Recall that [tex]\(\frac{1}{\left(\frac{a}{b}\right)} = \frac{b}{a}\)[/tex]. Applying this to our equation, we get:

[tex]\[ u = \frac{fv}{v - f} \][/tex]

So, we have successfully solved for [tex]\(u\)[/tex] in terms of [tex]\(f\)[/tex] and [tex]\(v\)[/tex]:

[tex]\[ u = \frac{f \cdot v}{v - f} \][/tex]

This is the formula for [tex]\(u\)[/tex].