# Graph sketching help

• Apr 5th 2008, 06:29 AM
Tumbleweed17
Graph sketching help
On seperate diagrams, sketch the graphs of:
a) y=(x+3)^2
and
b) y=(x+3)^2+k, where k is a positive constant.
=)
• Apr 5th 2008, 06:38 AM
TheEmptySet
Quote:

Originally Posted by Tumbleweed17
On seperate diagrams, sketch the graphs of:
a) y=(x+3)^2
and
b) y=(x+3)^2+k, where k is a positive constant.
=)

Remember our shifting rules for graphs

\$\displaystyle f(x-h)\$ shifts the graph of f(x) h units in the x direction.

\$\displaystyle f(x) + k\$ shifts the graph of f(x) k units in the y direction.

So we need to rewrite a) as follows

Note we will be shifting the graph of \$\displaystyle f(x)=x^2\$

\$\displaystyle f(x+3)=y=(x+3)^2=[x-(-3)]^2\$ so since we -3 = h we shift the graph of f(x) three units to the left.

for b)

we will shift f(x) up k units..

Good luck.
• Apr 7th 2008, 12:31 PM
Tumbleweed17
Reply to my plea for help =)
Thanks,
That was really useful, I didn't realise that it was a shift question!
Plus thanks for reminding me that
-3 = h and that you aren't always givent the function to tell you what the question is asking.
Thanks! =)