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

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

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.

2. Originally Posted by becca999

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

3. 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??

4. 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