# Sketching a graph

• Nov 26th 2009, 09:04 PM
Paymemoney
Sketching a graph
Hi guys
I didn't know where to put this, but I'm having trouble understanding what type of functions is this when i graph it:

\$\displaystyle (25-x^2)^{1/2}\$

http://img526.imageshack.us/img526/3081/function.png

P.S
• Nov 27th 2009, 03:12 AM
HallsofIvy
Quote:

Originally Posted by Paymemoney
Hi guys
I didn't know where to put this, but I'm having trouble understanding what type of functions is this when i graph it:

\$\displaystyle (25-x^2)^1/2\$

http://img526.imageshack.us/img526/3081/function.png

P.S

Your graph is simply wrong. If \$\displaystyle y= (25-x^2)^{1/2}\$ then \$\displaystyle y^2= 25 -x^2\$ or \$\displaystyle x^2+ y^2= 25\$. That last is a circle with center at (0,0) and radius 5. The original, the positive square root, is the upper semi-circle.

The graph you give appears to be from \$\displaystyle y= (x^2- 25)^{1/2}\$. That would give \$\displaystyle y^2= x^2- 25\$ so \$\displaystyle y^2- x^2= 25\$, a hyperbola. If that is correct, then your graph is the upper half of that hyperbola.