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VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Mathematical Methods CAS => Topic started by: wombifat on April 06, 2009, 03:48:19 pm

Title: graphing logarithms
Post by: wombifat on April 06, 2009, 03:48:19 pm

I'm using the Essentials book and it says to use transformations to find the intercepts, but I've just been letting x or y equal zero and solving for x or y.  Is there any advantage to doing it the way the book says? Mind you, transformations do my head in

Title: Re: graphing logarithms
Post by: TonyHem on April 06, 2009, 03:53:08 pm

Well it crosses the x-intercept at (1,0).
So a transformation parallel to the x-axis, just add or minus to the left/right accordingly and same for the Y-axis. Doesn't really matter imo.

Say..  y= loge(x+2)+3
-2 parallel to the x-axis
3 parallel to the y-axis

So from that original (1,0), minus 2, and 3 up. (-1,3)

Title: Re: graphing logarithms
Post by: wombifat on April 06, 2009, 03:54:59 pm

so it's ok if I don't do it the way the book does?

Title: Re: graphing logarithms
Post by: TonyHem on April 06, 2009, 03:56:47 pm

I don't think it really matters, I just think its easier to see it rather than writing all the stuff out.
I doubt its gonna have a question saying: "ONLY TRANSFORMATIONS, NO FINDING INTERCEPTS BY LETTING X = 0 and Y = 0"

Title: Re: graphing logarithms
Post by: wombifat on April 07, 2009, 10:12:53 pm

Yeah, but some methods won't work on EVERY question, or are very difficult to use on certain questions
but i just found out another text book tells you to do it this way so i should be fine (hopefully(yn))