Question

help on square roots and The little sign thingy that is confusing me

Answer 1

help

Answer 2

Well, that little sign thingy means at least 5 different things, so small wonder you find it confusing. It depends heavily on the context exactly what it means.

What problem are you working on?

Answer 3

a number that produces a specified quantity when multiplied by itself. "7 is a square root of 49"

Answer 4

Well what I am having trouble with is what the + over minus means? how you do you square a negative is it the same as a positive?

Answer 5

i know how to square so

Answer 6

You didn't answer my question. Depending on exactly what you are doing, it might mean different things.

Answer 7

Yes it is. so the square root of -64 is -8

Answer 8

"to square" a number simply means to multiply it by itself.

\(\large 2^2=2\cdot2=4\)
\(\large x^2=x\cdot x\)

Answer 9

Noooooo.... the square root of -64 is not defined in the real numbers!

Answer 10

No, the square root of -64 is NOT -8.

(-8)^2 = +64

Answer 11

\(\large (-8)^2=(-8)\cdot(-8)=64\)

Answer 12

Squaring is just multiplying. So just as with any multiplying,

positive x positive = positive
negative x positive = negative
negative x negative = positive

Answer 13

@DebbieG , could you help me with a question? Just to make sure I am right.

Answer 14

But back to the square root and the plus/minus symbol....

The square root is the number that you "square" to get the number under the symbol.

So \(\large \sqrt{16}=\sqrt{4\cdot4}=4\)

Now notice, it is also true that \(\large (-4)\cdot(-4)=16\). But here's the thing: we have DEFINED the square root operation to MEAN the POSITIVE number that, when multiplied by itself, gives you the number under the the sq root symbol, see what I mean?

Answer 15

post it separately please @m&msdoodle

Answer 16

So even though both \(\large 4\cdot4=16\) and \(\large (-4)\cdot(-4)=16\), only one of the two (that is, only one of 4 or -4) is DEFINED as the SQUARE ROOT of 16. That is:

\(\large \sqrt{16}=4\)

But... \(\large -\sqrt{16}=-4\)

So when you see something like \(\large \pm\sqrt{16}\), it is referring to BOTH the positive and the negative square root.

Answer 17

OK, I'm talking to myself. respond and tag me if you want help understanding.

Answer 18

No, you still are missing my point. That silly symbol can mean many things. It depends on what you are doing. So far, you have not stated a specific purpose.

Answer 19

Generally, the positive one is the "principal" square root.