# Equation to equal 25

1. Jul 2, 2013

### starphlo

Not sure where to put this...Could anyone give me a long equation to equal 25? I would like to put it on my son's birthday cake. He will be studying physics this fall in college. Thank you very much!

2. Jul 2, 2013

### MarneMath

Since no one else has replied, just do this:

$\int_{0}^{5}2xdx$

3. Jul 2, 2013

### DiracPool

How about the square root of 5^4.

$$\sqrt{5^4}$$

That should fit on a birthday cake quite succinctly

Edit: Marne's is pretty good too.

4. Jul 20, 2013

### collinsmark

Since he's going to be 25 years old, keeping the numbers '2' and '5' as the predominate numerals could be good.

For something really succinct, you might just try

$$5^2$$

Or if you want to get even crazier, you might try something like (slightly borrowing from MarneMath)

$$\sum_{n = 0}^\infty \frac{1}{2^n} - 2e^{5i \pi} +\int_2^5 2xdx$$

Last edited: Jul 20, 2013
5. Jul 20, 2013

### collinsmark

Or, throwing in a few more 2s and 5s,

$$\frac{5}{2}\sum_{n = 0}^\infty \frac{1}{2^n} - e^{(2)(5)i \pi} +\int_2^5 2xdx$$

Or, if you prefer,

$$\frac{5}{2}\sum_{n = 0}^\infty \frac{1}{2^n} + e^{25 i \pi} +\int_2^5 2xdx$$

Be mindful of matching the "+" vs "-" and the "(2)(5)" vs "25" in each of the "e" term of each formula. It makes a difference.