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Small math question

How do you write the domain of cot(x) in interval notation? Also what are the points of discontinuity of ln(x+1) if there is any?

August 25, 2012

9 Comments • Newest first

Mathematician

[quote=radkai]@Mathematician: Right ^_^[/quote]

Okay, Thanks. I think I'm getting this whole continuity thing now. UwU

Reply August 26, 2012
Mathematician

[quote=radkai]Can't do ln 0 bro. x > -1. Point of discontinuity would be wrong in this case. How can it be discontinuous when it wasn't even continuous to being with? Better way of describing would be domain.[/quote]

So there would be no points of discontinuity right? Since its a continuous graph?

Reply August 26, 2012
delightful1

i dont know too bad

Reply August 26, 2012 - edited
radkai

[quote=ChewyC]ln(x+1), x has to more than or equal to -1 cause you cant get negative ln.[/quote]

Can't do ln 0 bro. x > -1. Point of discontinuity would be wrong in this case. How can it be discontinuous when it wasn't even continuous to being with? Better way of describing would be domain.

Reply August 26, 2012 - edited
RyuuzakiDN

Cot(x) is defined over spaced out multiples of (0<x<pi/2), but there's no way to write that in interval form. You can write out the [i]range[/i] of Cot(x) as (-∞,∞), but there's no way you can express the domain in interval form.

As for the second question:
[quote=ChewyC]ln(x+1), x has to more than or equal to -1 cause you cant get negative ln.[/quote]
He has it correct. ln(x+1) is asymptotic to the line x=-1, so there are points of discontinuity when x ≤ -1.

[quote=ImNoMerchant]Is this Calculus? or perhaps Pre-Calculus?[/quote]
It looks like algebra II to me.

Reply August 26, 2012 - edited
ImNoMerchant

Is this Calculus? or perhaps Pre-Calculus?

Reply August 26, 2012 - edited
Mathematician

[quote=FTWJayChou]cot (x) = 1/tanx = cos x/ sin x
That would mean, cot (x) is discontinuous on the points where sin (x) = 0 because you can't have (cos x)/ 0.

I'm not sure how your teacher exactly wants it but it should be something similar to:

D: {xER || x =/= +/- n*pi}[/quote]

Oh haha silly me I put the wrong function. I meant to ask for the discontinuities of ln(x+1)
Also thanks for the notion thing.

Reply August 25, 2012 - edited
dadadada

lol ...... im in 10th grade

Reply August 25, 2012 - edited