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Section 1.10 : Common Graphs

15. Without using a graphing calculator sketch the graph of \(\displaystyle 25{\left( {x + 2} \right)^2} + \frac{{{y^2}}}{{4}} = 1\).

Show Solution

This is just an ellipse that is almost in standard form. With a little rewrite we can put it into standard form as follows,

\[\frac{{{\left( x+2 \right)}^{2}}}{{}^{1}/{}_{25}}+\frac{{{y}^{2}}}{4}=1\]

We can now see that the ellipse has a center of \(\left( { - 2,0} \right)\) while the left/right most points will be \(\frac{1}{5} = 0.2\) units away from the center and the top/bottom most points will be 2 units away from the center. Here is a quick sketch of the ellipse.

The graph of the ellipse \(25{\left( {x + 2} \right)^2} + \frac{{{y^2}}}{4} = 1\).  The ellipse has center (-2,0) and is tall and narrow.  Its leftmost and rightmost points are (-2.2,0) and (-1.8,0) and its lowest and highest points are (-2,-2) and (-2,2).