# Finding Intercepts

• Apr 21st 2008, 03:04 PM
BostonBlaze
Finding Intercepts
The following problem has me stumped:

List the intercepts and test for symmetry for the following problem:

y^2 = x + 4
• Apr 21st 2008, 03:08 PM
Mathstud28
Quote:

Originally Posted by BostonBlaze
The following problem has me stumped:

List the intercepts and test for symmetry for the following problem:

y^2 = x + 4

$|y|=\sqrt{x+4}$...so for $|0|=\sqrt{4+x}$ which occurs at x=-4....after that to attain y intercept we first need to solve for y $|y|=\sqrt{4+x}\Rightarrow{y=\pm\sqrt{4+x}}$....so for $y(0)=\pm\sqrt{4+0}=\pm{2}$...and for symmetry...since it is NOT a function it is x-axis symmetric...it is not to either hte origin or the y-axis putting in $y(-x)$ will reveal that
• Apr 22nd 2008, 10:47 AM
earboth
Quote:

Originally Posted by Mathstud28
$|y|=\sqrt{x+4}$...so for $|0|=\sqrt{4+x}$ which occurs at x=-4....after that to attain y intercept we first need to solve for y $|y|=\sqrt{4+x}\Rightarrow{y=\pm\sqrt{4+x}}$....so for $y(0)=\pm\sqrt{4+0}=\color{red}\pm{\bold{2}}$...and for symmetry...since it is NOT a function it is x-axis symmetric...it is not to either hte origin or the y-axis putting in $y(-x)$ will reveal that

Sorry, but there is a small typo.
• Apr 22nd 2008, 11:25 AM
Isomorphism
Quote:

Originally Posted by BostonBlaze
The following problem has me stumped:

List the intercepts and test for symmetry for the following problem:

y^2 = x + 4

Have you tried plotting the graph? Do you know co-ordinate geometry ? Do you know what is a parabola?
• Apr 22nd 2008, 04:34 PM
Mathstud28
Quote:

Originally Posted by earboth
Sorry, but there is a small typo.

THanks for catching that typo!