Math Question

[Baal]

Originally posted by Atrocities:
You guys in five short Posts or so just totally ruined any desire I might have had to return to school.

Atrocities, you are killing me old boy. Wait for me to get my hands on a camera and I'll show you the most painful math you will ever see.

(I will be back with a picture in a few days; I promise you)

[Dragonswrd]

I might have to take another look at my math books to be able to do trig again, but from what I remember about trig and algebra they were easier when I went back to school to get my degree.

[Phoenix-D]

Originally posted by Atrocities:
You guys in five short Posts or so just totally ruined any desire I might have had to return to school.

Should I post some of my old calc homework and really kill any desire?

Or maybe some statatics..

SD = sqrt((sum of y deviations - y average)^2)/n)

[Baal]

Should I post some of my old calc homework and really kill any desire?

You mean kind like...

[(d^2)z/(dt)^2] + [k/m*z] - [kL/m] + [C/m(dz/dt)] - [g] = [kA/m*sin(wt)]

I have a test involving this problem in about an hour and a half.

[Phoenix-D]

Yep. Fortunately I didn't have to get too deep into calc for my major..even the course I took was a pain.

[Cipher7071]

But isn't there always a positive AND negative number for any square root? If x is 0 for example you get f(0)=sqrt(4) Isn't that 2 or -2? Can someone explain why you don't count the -2?

Geo, this is probably because you are working with functions. A function may only have one value in the range for each value in the domain.
So, in this case, the function sqrt() is defined to be positve .

[geoschmo]

Originally posted by Cipher7071:

quote:

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But isn't there always a positive AND negative number for any square root? If x is 0 for example you get f(0)=sqrt(4) Isn't that 2 or -2? Can someone explain why you don't count the -2?

Geo, this is probably because you are working with functions. A function may only have one value in the range for each value in the domain.
So, in this case, the function sqrt() is defined to be positve .

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Ok, but isn't that circular logic? To me it sounds like you are saying that the square root of a number is always positive, because if it's negative then it's not a function. But the square root being positive is what makes it a function. How do you know it's a function, other then the fact that I typed it in function notation? Because there are times they will give you a problem in function notation and ask you if it is indeed a function.