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Power Seller Center (guest) 06 Nov 2013 00:43
in discussion Hidden / Per page discussions » Power Seller College Newbie

Hello everyone, I just joined the forum. I have seen a lot of interesting stuff here. I hope to be able to participate in discussions and offer my input as well!

Cheers!

by Power Seller Center (guest), 06 Nov 2013 00:43
08 Aug 2012 03:04
in discussion Hidden / Per page discussions » Power Seller College Newbie

**Hello all, just joined the forum. Saw a lot of interesting stuff here and maybe I'm able to share some too along the way

Cheers!**

Power Seller College Newbie by , 08 Aug 2012 03:04

I am Lysco Chimney….

Well let me tell you all about my self.

I am a fun loving, cheerful girl who takes every responsibility seriously, loves watching movies, reading books and playing games on PS3.

Umm, well I guess thats sufficient for the time being,

Lemme know about you all :)

Lysco Chimney

Newbie Lysco Chimney here..:)) by , 28 May 2012 03:08
Victoria Kim (guest) 20 Jul 2011 17:52
in discussion Hidden / Per page discussions » Elem Algebra

I think it is helpful for the students to put in numbers for the axes, especially if they are trying to match it to a graph they already have. For example, you can say plot y=3x+5 from -10 to 10, and it will show that part of the axes.

by Victoria Kim (guest), 20 Jul 2011 17:52
Victoria Kim (guest) 20 Jul 2011 17:35
in discussion Hidden / Per page discussions » Elem Algebra

by Victoria Kim (guest), 20 Jul 2011 17:35
08 Oct 2009 20:54
in discussion Hidden / Per page discussions » Upper Level Courses

I have not been able to find any way of entering a query to WA that will find information on lines in 3-space. I have tried giving the parametric form of a particular line, typing the words "line in space", or 3 dimensional line. I tried the Mathematica input for a parametric line in space and nothing works. Any suggestions?

Lines in 3-Space by , 08 Oct 2009 20:54
31 Jul 2009 17:10
in discussion Hidden / Per page discussions » Elem Algebra

There has been at least 1 change since June 22 in Walpha outputs. By July 26, the query "y=5+3x" produced no graph at all rather than the two described in my previous post, and neither "graph y=5+3x" nor "plot y=5+3x" produced a graph. But as Gizem Karaali pointed out to me, "line y=5+3x" will produce a line and the axes do cross at (0,0).

changes regarding y=5+3x by , 31 Jul 2009 17:10
29 Jul 2009 13:34
in discussion Hidden / Per page discussions » Calculus II

I think the problem is just how the axes are set up (in any graph). Looking at the tickmarks for 2 and 1.5, it looks like where the axes cross when you ask W|alpha "hyperbolic cosine", they actually cross when y=1. I'm not sure how to get W|alpha to make the axes cross at the origin. Anybody?

Re: Hyperbolic cosine by , 29 Jul 2009 13:34
Steve DeLong (guest) 25 Jul 2009 22:53
in discussion Hidden / Per page discussions » Calculus II

When one attempts to plot the graph of hyperbolic cosine, we see a graph that passes through the origin, which is not correct if the graph is done on the real plane. I can't tell if the program is graphing using complex values or not; any thoughts?

Steve

Hyperbolic cosine by Steve DeLong (guest), 25 Jul 2009 22:53
Bruce Yoshiwara (guest) 22 Jun 2009 17:39
in discussion Hidden / Per page discussions » Elem Algebra

The query "y=5+3x" will result in two graphs, the first of which appears to show a line with negative vertical intercept.

The truth is that the vertical line marked with the vertical scale is not the y-axis, but x=-1.69.

The query "y=5+3x, x from 0 to 10" will result in a single graph that appears to show a line through the origin, but in this case the horizontal line marked with the horizontal scale is not the x-axis, but y=5.

Although I recognize that graphs often do not show the axes, I'd like a soft introduction for my developmental students.

How do we force W|Alpha to put the "AxesOrigin" at (0,0)?

forcing the axes to cross at (0,0) by Bruce Yoshiwara (guest), 22 Jun 2009 17:39
Bruce Yoshiwara (guest) 17 Jun 2009 20:49
in discussion Hidden / Per page discussions » Calculus II

If you enter

1/(2+cos(x))

at W|Alpha, you get a couple of things worthy of discussion. The first is that both graphs appear to drop below the x-axis (which would be surprising for a function that is always positive), until you notice that the horizontal line showing the scale is not the x-axis at all but y = 0.4.

The fun part for Calculus is that, because the given continuous function is positive everywhere, its anti-derivative is increasing (and differentiable) for all values of x. However, the given expression for the indefinite integral (in W|Alpha or any other CAS using the Risch algorithm) is periodic: f(x + 2pi) = f(x).

And no continuous periodic function is increasing everywhere.

Tom (guest) 12 Jun 2009 20:24
in discussion Hidden / Per page discussions » Calculus I

integrate Piecewise[1,x<0},{2,x>0] from -1 to 5 does the job very easily. (But I learned this using Jay's form as a starter.) However this fails if Piecewise is not capitalized. I sent a suggestion in this direction to W|A.

Re: by Tom (guest), 12 Jun 2009 20:24
04 Jun 2009 14:32
in discussion Hidden / Per page discussions » Calculus I

Thanks, Jay. This is actually pretty handy. I like that the integration comes with a shaded graph to help visualize it.

Re: Integrating PW Functions by , 04 Jun 2009 14:32
jay (guest) 04 Jun 2009 03:54
in discussion Hidden / Per page discussions » Calculus I

Piecewise function can be entered using Mathematica syntax, for example,

http://www54.wolframalpha.com/input/?i=Piecewise%5B%7B%7B1%2Cx%3C0%7D%2C%7B2%2Cx%3E0%7D%7D%5D

and then it can do integrate, etc, using this

http://www54.wolframalpha.com/input/?i=integrate+Piecewise%5B%7B%7B1%2Cx%3C0%7D%2C%7B2%2Cx%3E0%7D%7D%5D+from+x%3D-1+to+x%3D2

but there should be better way….

by jay (guest), 04 Jun 2009 03:54