## unimatix one year ago why are these two equations equal

1. unimatix

$\frac{ u ^{2}}{ 1+u^2 } = 1 - \frac{ 1 }{ 1+u^2 }$

2. unimatix

basic algebra i'm sure. just drawing a blank here.

3. dan815

you have to take the common denominator

4. dan815

just like how you need common denominator to add fractions now your denominator just happens to be some expression instead of a number

5. dan815

|dw:1442717373661:dw|

6. dan815

|dw:1442717414388:dw|

7. unimatix

okay I see it now.

8. unimatix

thanks!

9. dan815

welcome