Pre-Cal Help: How do you know what kind of graph based on the equation?

Question

I need help on classifying what kind of graph would the problem be (i.e, circle, parabola, ellipse, or hyperbola) based on an equation given. Can someone give a clear explanation on how to classify?
 
I'm stuck on these three problems:

x^2+4y^2-6x+16y+21=0 

y^2-6y-4x+21=0

4y^2-2x^2-4y-8x-15=0

Matthew · Accepted Answer

To do this you need to see how the expression might be rearranged and check if it fits the standard form of an equation for a particular kind of graph.

E.g. For the first one, this can be rearranged into:
(x-3)^2+4 (y+2)^2=4
which is the form of an ellipse:
http://www.wolframalpha.com/input/?i=%28x-3%29^2%2B4+%28y%2B2%29^2%3D4

? · Answer

First graph the function, the something it extremely is under the x-axis (y=0) desires to be meditated back to the helpful portion of the axis. Ex. whilst graphing f(x)=y=x, draw the line and then mirror the section left of the muse up above the x-axis. further with y=x^3, etc.

Trending News

Pre-Cal Help: How do you know what kind of graph based on the equation?

2 Answers