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VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Mathematical Methods CAS => Topic started by: ngRISING on September 17, 2009, 10:10:34 pm

Title: All the graphs for maths methods
Post by: ngRISING on September 17, 2009, 10:10:34 pm: hey guys,
i was wondering does anyone have the sheet with all the basic graphs i would need to know for maths methods like e^x, log graphs etc. cause im really really bad with graphs =S . need something to memorise. =D. ty ty .
Title: Re: All the graphs for maths methods
Post by: Flaming_Arrow on September 17, 2009, 10:12:05 pm: i wouldnt recommend memorising graphs, sub in random x values and dy/dx for tp's if it helps u sketch it
Title: Re: All the graphs for maths methods
Post by: ngRISING on September 17, 2009, 10:19:09 pm: lolol. i wanna memorise some at least for tech free. idk what loge(x) looks like without a calc. just need a basic idea of them lol.
Title: Re: All the graphs for maths methods
Post by: kurrymuncher on September 17, 2009, 10:20:23 pm: Quote from: ngRISING on September 17, 2009, 10:19:09 pm
lolol. i wanna memorise some at least for tech free. idk what loge(x) looks like without a calc. just need a basic idea of them lol.

If you dont know what loge(x) looks like, you better get off VN and hit the books.
Title: Re: All the graphs for maths methods
Post by: ngRISING on September 17, 2009, 10:26:03 pm: hitting the books hard LOL. spent the past few hours on revise in a month + check points. im kinda screwed for mm. forgot some surd rules too ==' .
Title: Re: All the graphs for maths methods
Post by: pHysiX on September 18, 2009, 07:03:48 pm: lol nguyen you have a calculator. just sketch on calc, then look for significant points (x, y ints, t.pts) and sktech onto a sheet of paper. 2 babes with one move: 1: U know the shape and practise for tech active, 2: you are writing it down, there'll be something to memorise =]
Title: Re: All the graphs for maths methods
Post by: NE2000 on September 18, 2009, 07:22:03 pm: It's never too late to try and understand rather than try and memorize. If you understand you pretty much won't need to revise it'll just be ingrained in your head.

For the log graph for example, of basic form y = logex.
- When x = 0 or x < 0, y is undefined. (explanation u should know but if you don't $e^{y} = x$ and as $e^{y} > 0$ for all x, $x > 0$ . The result? the graph will only appear on the right side and there will be an asymptoe at x = 0

- When y = 0 (for x-intercept), x = 1 (using log laws). Hence (1,0) is x-intercept

- now for the shape of the graph. Think about it this way (while looking at graph on your calculator). Think about it in terms of $e^{y} = x$ . When y > 0, as you increase y, x increases exponentially in this case. So for small increases in y you get large increases in x. Take that idea to your log graph, that as you get to larger values, small increases in y get large increases in x. For y < 0, when you make y even smaller, x just gets closer to zero. Take that idea to the bottom half of your log graph, that is when y is small the graph is getting close to x=0 (although never touching it)

And that basically somes up log graphs (the rest is just transformations)