Math Problem (Help ASAP!) - Tilted Forum Project Discussion Community

Munku · 12-13-2004, 08:03 PM

Evaluate. Give mathematical reasons for your answer.

Please some one help me quick!

Edit: Would the answer just be C due to a jump discontinuity or something? I doubt it but I got nothing..

soma · 12-13-2004, 08:10 PM

Wouldn't that just be negative one? (I could very well be WAY off.)

mandal · 12-13-2004, 08:23 PM

i believe it's undefined. haven't done it in a while, but when you approach from the left you get one answer and from the right you get another answer, therefore, it's undefined

sandinista · 12-13-2004, 08:27 PM

Yeah, it's called the sigma function or something. The limit is undefined, but if there is a plus or a minus sign in the limit notation, then the answer is going to be + or - 1 depending on whether or not it's a + or a - in the limit. Hard to explain.

MageB420666 · 12-13-2004, 09:21 PM

edited - checked math, it is undefined since approaching from left the limit is different than approaching from right, so limit is undefined.

sandinista · 12-13-2004, 09:24 PM

Quote:

Originally Posted by MageB420666

Use L'Hospital's rule.

in this case f(x) = |x-c| and g(x) = x-c, so f'(x) = 1 and g'(x) = 1, so according to L'Hospital's rule, the limit is 1

The problem with that is the absolute value thrown in there. Thus, if you approach the limit from the left side, the function is negative 1, but if you approach it from the right side, the function is positive 1. For that reason, L'Hospital's rule is wrong. Good rule though.

MageB420666 · 12-13-2004, 09:26 PM

Quote:

Originally Posted by sandinista

The problem with that is the absolute value thrown in there. Thus, if you approach the limit from the left side, the function is negative 1, but if you approach it from the right side, the function is positive 1. For that reason, L'Hospital's rule is wrong. Good rule though.

realized that half a second after I hit the submit button and changed it, thanks though

bobophil · 12-14-2004, 05:51 PM

ummm... False!

Karkaboosh1 · 12-17-2004, 02:37 PM

from the left, you get 1/-1, from the right you get 1/1. because as x approaches c from the left and it reaches teh limit, it will become just less than 0, and frmo teh right just over zero, since the numerator is always positive and the denominator is + or -, you get 1 or - 1. if the limit is reached at x = c, then there is no solution since x - c != 0

12-13-2004, 08:03 PM	#1 (permalink)
Munku Lost Location: Florida	Math Problem (Help ASAP!) Evaluate. Give mathematical reasons for your answer. Please some one help me quick! Edit: Would the answer just be C due to a jump discontinuity or something? I doubt it but I got nothing.. Last edited by Munku; 12-13-2004 at 08:07 PM..

12-13-2004, 08:27 PM	#4 (permalink)
sandinista Tilted	Yeah, it's called the sigma function or something. The limit is undefined, but if there is a plus or a minus sign in the limit notation, then the answer is going to be + or - 1 depending on whether or not it's a + or a - in the limit. Hard to explain. __________________ "Nature herself makes the wise man rich." -Cicero

12-13-2004, 09:21 PM	#5 (permalink)
MageB420666 <Insert wise statement here> Location: Hell if I know	edited - checked math, it is undefined since approaching from left the limit is different than approaching from right, so limit is undefined. __________________ Apathy: The best outlook this side of I don't give a damn. Last edited by MageB420666; 12-13-2004 at 09:25 PM..

12-13-2004, 08:10 PM	#2 (permalink)
soma Addict Location: USA	Wouldn't that just be negative one? (I could very well be WAY off.)

12-13-2004, 08:23 PM	#3 (permalink)
mandal Crazy	i believe it's undefined. haven't done it in a while, but when you approach from the left you get one answer and from the right you get another answer, therefore, it's undefined

12-14-2004, 05:51 PM	#8 (permalink)
bobophil Tilted	ummm... False!

12-17-2004, 02:37 PM	#9 (permalink)
Karkaboosh1 Upright	from the left, you get 1/-1, from the right you get 1/1. because as x approaches c from the left and it reaches teh limit, it will become just less than 0, and frmo teh right just over zero, since the numerator is always positive and the denominator is + or -, you get 1 or - 1. if the limit is reached at x = c, then there is no solution since x - c != 0