/sci/ - Omg spot the error (yes I do know what it is)

Name: Anonymous 2006-09-16 8:29

1/(-1)=(-1)/1
sqrt(1/(-1))=sqrt((-1)/1)
1/i=i/1
1=-1

OMG!!!

Name: Anonymous 2006-09-16 8:52

Oh my god, spot the error (Yes, I do know what it is).
FIXED.
You're Welcome.

Name: Anonymous 2006-09-16 10:16

Actally, I prefer to leave my implicit sarcasm.

Name: Anonymous 2006-09-16 10:42

you can't just go sqrting all over the place

Name: Anonymous 2006-09-16 11:20

1/-1 = -1
-1/1 = -1

Name: Anonymous 2006-09-16 11:26

>>4
You might know the answer... elaborate.

Name: Anonymous 2006-09-16 11:57 (sage)

>>6
sqrt(a/b)=sqrt(a)/sqrt(b) doesn't work for negative and complex values

Name: Anonymous 2006-09-16 12:48

>>6
1/-1 = -1
-1/1 = -1

Name: Anonymous 2006-09-16 15:10

>>7
correct.

And I don't know what 8 and 5 are going on about.

Name: Anonymous 2006-09-16 16:06

The actual answer isn't that sqrt(a/b) = sqrt(a)/sqrt(b) doesn't work, it's that sqrt(1) = +or- 1

Name: Anonymous 2006-09-16 16:10 (sage)

>>10
if x^2=1, then x=1 or x=-1, but sqrt is defined to output only a single value.

Name: Anonymous 2006-09-16 17:07

>>11
You seem to be confusing "square root" with "principal square root."

Name: Anonymous 2006-09-16 17:47 (sage)

>>12
NO U
sqrt isn't simply an abbreviation of square root, it's a function also known as √.
(and SPOILER: it doesn't return the set of all square roots)

Name: Anonymous 2006-09-16 19:13

>>13
Ah, apologies. I forgot that you were the God of Notation, with the ability to decide for everyone what an ambiguous abbreviation means.

Name: Anonymous 2006-09-16 19:29

>>14
13 is right. When you square root something, it comes out positive. (unless it's negaive before you start)

Name: Anonymous 2006-09-16 19:30 (sage)

>>14
that's ok

Name: Anonymous 2006-09-17 1:38

>>9
>>11
1/-1 = -1
-1/1 = -1 !!!

Name: Anonymous 2006-09-17 1:44

1/(-1)=(-1)/1 = -1
sqrt-1 = sqrt-1
i=i
i=???

Name: Anonymous 2006-09-17 5:25

>>17
>>18

Writing out different bits of working shows nothing and has no purpose whatsoever. You're supposed to resolve the problem created by the original working.

Name: Anonymous 2006-09-17 9:34

>>10 is right. In sqrt(a/b) = sqrt(a)/sqrt(b) a and b has to be positive.

Also, sqrt(-1) = +i or -i and sqrt(1) = +1 or -1 but that's not really relevant since step 2 going to 3 in >>1 is wrong.

Name: Anonymous 2006-09-17 11:29

http://www.math.toronto.edu/mathnet/falseProofs/second1eq2.html

Both parties are right.

Name: Anonymous 2006-09-18 4:06

>>19
Yes the best way to resolve a problem is to work with a broken problem.
Given the initial statement he square rooted and showed the problem. He didn't write out different bits, he wrote the exact same problem, just correctly.

Omg spot the error (yes I do know what it is)

1 Name: Anonymous 2006-09-16 8:29

2 Name: Anonymous 2006-09-16 8:52

3 Name: Anonymous 2006-09-16 10:16

4 Name: Anonymous 2006-09-16 10:42

5 Name: Anonymous 2006-09-16 11:20

6 Name: Anonymous 2006-09-16 11:26

7 Name: Anonymous 2006-09-16 11:57 (sage)

8 Name: Anonymous 2006-09-16 12:48

9 Name: Anonymous 2006-09-16 15:10

10 Name: Anonymous 2006-09-16 16:06

11 Name: Anonymous 2006-09-16 16:10 (sage)

12 Name: Anonymous 2006-09-16 17:07

13 Name: Anonymous 2006-09-16 17:47 (sage)

14 Name: Anonymous 2006-09-16 19:13

15 Name: Anonymous 2006-09-16 19:29

16 Name: Anonymous 2006-09-16 19:30 (sage)

17 Name: Anonymous 2006-09-17 1:38

18 Name: Anonymous 2006-09-17 1:44

19 Name: Anonymous 2006-09-17 5:25

20 Name: Anonymous 2006-09-17 9:34

21 Name: Anonymous 2006-09-17 11:29

22 Name: Anonymous 2006-09-18 4:06