# sketching curves-transformation curves f(x)!!!!

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• Dec 2nd 2006, 01:50 AM
becca999
sketching curves-transformation curves f(x)!!!!
Hi, not sure what to do here. please help.

find the equations of the curves y=f(x+2) and y=f(x)+2, in terms of x, and use these equations to find the coordinates of the points where these curves cross the y-axis.
• Dec 2nd 2006, 01:54 AM
CaptainBlack
Quote:

Originally Posted by becca999
Hi, not sure what to do here. please help.

find the equations of the curves y=f(x+2) and y=f(x)+2, in terms of x, and use these equations to find the coordinates of the points where these curves cross the y-axis.

It looks like you have not given us enough information here. I think we will
need to know something about f.

RonL
• Dec 2nd 2006, 05:11 AM
becca999
well it a says y=f(x) where f(x)=(x-1)(x+2) but then how do you work out the equations of the curves y=f(x+2) and y=f(x)+2 in therms of x and finding coordinates??
• Dec 2nd 2006, 06:55 AM
CaptainBlack
Quote:

Originally Posted by becca999
well it a says y=f(x) where f(x)=(x-1)(x+2) but then how do you work out the equations of the curves y=f(x+2) and y=f(x)+2 in therms of x and finding coordinates??

If \$\displaystyle f(x)=(x-1)(x+2)\$, then

\$\displaystyle
f(x+2)=((x+2)-1)((x+2)+2)=(x+1)(x+4)
\$

so the equation of \$\displaystyle y=f(x+2)\$ is:

\$\displaystyle y=(x+1)(x+4)\$

similarly:

\$\displaystyle y=f(x)+2=(x-1)(x+2)+2=x^2+x=x(x+1)\$

so:

\$\displaystyle y=x(x+1)\$

RonL