is √2+√2 = 2√2 or √4?

Great answer, CPhill!

I just want to point out something to Anonymous:

Your reasoning is good:) but you forgot one small detail. 2√2 is equal to √8, not 8. The square root sign makes a big difference!

Its neither because 2√2 is 8 and √4 is 2. √2+√2 is 2.8284271247461901, as for what it can be equal to, i dont know.

s √2+√2 = 2√2 or √4

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This kind of stuff use to confuse me, too.  Here's a hint....when confronted by something that you're not sure of .... use some numbers that you know and see if this leads you to the correct answer !!

For instance ......is √9+√9 = 2√9 or √18   ???

Well....√9+√9 = 3 + 3 = 6

And....... 2√9 = 2*3 = 6

Mmmmm...that looks a lot like the first answer, doesn't it??

Think about √18.....the √16 = 4 and the √25 = 5...so the √18 must be between 4 and 5 and that's certainly < 6 !!

Can you answer your own question, now??