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VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Mathematical Methods CAS => Topic started by: vea on October 25, 2010, 07:17:54 pm

Title: Does the domain of a graph change when transformations are applied to it?
Post by: vea on October 25, 2010, 07:17:54 pm: As the title states, here is an example:

The graph of $y=cosx$ with domain $0\le x\le2\pi$ is dilated by a factor of 2 from the y-axis.

The equation is now $y=cos(\frac{x}{2})$ and so it has a period of $4\pi$ . Do we change the domain to be $0\le x\le4\pi$
Title: Re: Does the domain of a graph change when transformations are applied to it?
Post by: itolduso on October 25, 2010, 09:46:19 pm: domain is part of a function. when a function is transformed so is its domain
Title: Re: Does the domain of a graph change when transformations are applied to it?
Post by: sajib_mostofa on October 25, 2010, 09:49:15 pm: Quote from: vea on October 25, 2010, 07:17:54 pm
As the title states, here is an example:

The graph of $y=cosx$ with domain $0\le x\le2\pi$ is dilated by a factor of 2 from the y-axis.

The equation is now $y=cos(\frac{x}{2})$ and so it has a period of $4\pi$ . Do we change the domain to be $0\le x\le4\pi$

Correct. Just remember that the domain of a function only changes if theres been a dilation from the y-axis or a translation in the x direction.
Title: Re: Does the domain of a graph change when transformations are applied to it?
Post by: vea on October 26, 2010, 07:08:01 pm: I understand the concept now, thanks guys