Finding Intercepts

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• 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

$\displaystyle |y|=\sqrt{x+4}$...so for $\displaystyle |0|=\sqrt{4+x}$ which occurs at x=-4....after that to attain y intercept we first need to solve for y $\displaystyle |y|=\sqrt{4+x}\Rightarrow{y=\pm\sqrt{4+x}}$....so for $\displaystyle y(0)=\pm\sqrt{4+0}=\pm{2}$...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 $\displaystyle y(-x)$ will reveal that
• Apr 22nd 2008, 10:47 AM
earboth
Quote:

Originally Posted by Mathstud28
$\displaystyle |y|=\sqrt{x+4}$...so for $\displaystyle |0|=\sqrt{4+x}$ which occurs at x=-4....after that to attain y intercept we first need to solve for y $\displaystyle |y|=\sqrt{4+x}\Rightarrow{y=\pm\sqrt{4+x}}$....so for $\displaystyle y(0)=\pm\sqrt{4+0}=\color{red}\pm{\bold{2}}$...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 $\displaystyle y(-x)$ 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!