How does pi(y/2π)² = y²/4π?

[powp]

How does pi(y/2pi)^2 = y^2/4pi?

I am confussed.

Thanks

 

[Nylex]

$$\pi \left(\frac {y} {2\pi}\right)^2 = \frac {\pi y^2} {(2\pi)^2} = \frac{\pi y^2} {4\pi^2} = \frac {y^2} {4\pi}$$

 

[dextercioby]

In short and abstract form

$$\left(\frac{a}{b}\right)^{2}=\frac{a^{2}}{b^{2}}$$

and

$$\left(ab\right)^{2}=a^{2}b^{2}$$

,okay?

Daniel.

 

[powp]

what happens to the pi on top?

 

[Jameson]

It cancels with one of the pi's on the bottom.

$$\frac{\pi y^2} {4\pi^2} = \frac{\pi y^2} {4\pi*\pi} = \frac{\pi(y^2)}{\pi(4\pi)}$$

Do you see how you can cancel?

 

[powp]

Yes Thanks