504 views

### Rearranging formulae

Rearrange 1/u + 1/v = 1/f

to make u the subject of the formula. Give your answer in its simplest form.

There are a number of ways to approach this problem.

By subtracting 1/v on both sides we get 1/u as the subject of the equation:

1/u = 1/f - 1/v

The inverse of the equation can be found to make the subject u:

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

This can be simplified by multiplying by fv/fv:

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

As fv/fv is equal to one, this can be simplified further to give the final answer:

u = fv/(v-f)

10 months ago

Answered by Robert, a GCSE Maths tutor with MyTutor

## Still stuck? Get one-to-one help from a personally interviewed subject specialist

#### 807 SUBJECT SPECIALISTS

£20 /hr

Degree: Economics (Bachelors) - Cambridge University

Subjects offered:Maths, Economics+ 2 more

Maths
Economics
-Personal Statements-
-Oxbridge Preparation-

“Economics Graduate from Cambridge, wanting to share my passion for the discipline”

£18 /hr

Degree: MPhys Physics (Integrated Masters) - Oxford, St Edmund Hall University

Subjects offered:Maths, Physics+ 2 more

Maths
Physics
Further Mathematics
.PAT.

“Enthusiastic and experienced Oxford undergraduate with a passion for maths and physics”

£18 /hr

Degree: Economics and Statistics (Integrated Masters) - St. Andrews University

Subjects offered:Maths, Business Studies+ 1 more

Maths
-Personal Statements-

“I study Economics and Statistics because I enjoy learning about the role mathematics and statistics plays in our everyday.”

MyTutor guarantee

Currently unavailable: for regular students

Degree: Engineering Mathematics (Bachelors) - Bristol University

Subjects offered:Maths, Physics+ 2 more

Maths
Physics
Computing
-Personal Statements-

“Engineering Mathematics Undergrad available to tutor Maths, Physics and Computer Science at IB/GCSE level.”

MyTutor guarantee

|  12 completed tutorials

### You may also like...

#### Other GCSE Maths questions

How do I use Pythagorus' Theorum?

How to solve the simultaneous equations of 3x + 2y = 9 and x-y = 3

How to factorise simple quadratic equations?

Prove that (2n+3)^2-(2n-3)^2 is a multiple of 8 for positive integer values of n

We use cookies to improve your site experience. By continuing to use this website, we'll assume that you're OK with this.