• Nov 13th 2006, 09:46 PM
coopsterdude
Hi everyone,

How do I write this equation in the standard form and then graph it. I don't how I could get a standard circle or a hyperbola equation from the following. I am to graph the equation after writing it but I'm sure I can if I can write it in the correct standrd form. Here it is.

9x^2 - y^2 = -16

Thanks
• Nov 14th 2006, 03:00 AM
OReilly
Quote:

Originally Posted by coopsterdude
Hi everyone,

How do I write this equation in the standard form and then graph it. I don't how I could get a standard circle or a hyperbola equation from the following. I am to graph the equation after writing it but I'm sure I can if I can write it in the correct standrd form. Here it is.

9x^2 - y^2 = -16

Thanks

You can solve equation for $\displaystyle y$:
$\displaystyle \begin{array}{l} 9x^2 - y^2 = - 16 \\ y^2 = 9x^2 + 16 \\ y = \sqrt {9x^2 + 16} \\ \end{array}$

Then you can graph function: $\displaystyle f(x) = \sqrt {9x^2 + 16}$

Here is graph:
• Nov 14th 2006, 03:22 AM
topsquark
Quote:

Originally Posted by OReilly
You can solve equation for $\displaystyle y$:
$\displaystyle \begin{array}{l} 9x^2 - y^2 = - 16 \\ y^2 = 9x^2 + 16 \\ y = \sqrt {9x^2 + 16} \\ \end{array}$

Then you can graph function: $\displaystyle f(x) = \sqrt {9x^2 + 16}$

Here is graph:

Note though that when you take the square root you have to provide BOTH possibilities: + and -:
$\displaystyle y = \pm \sqrt{9x^2+16}$

-Dan
• Nov 14th 2006, 03:44 AM
OReilly
Quote:

Originally Posted by topsquark
Note though that when you take the square root you have to provide BOTH possibilities: + and -:
$\displaystyle y = \pm \sqrt{9x^2+16}$

-Dan

Yes, minus for me... :D