Graph the quadratic functions y = -2x^2 and y = -2x^2 + 4 on a seperate piece of paper. Using those graphs, compare and contrast the shape and position of the graphs.

Question

anonymous · Answer

I'm not sure how to graph them.

accessdenied · Answer

Well, this is a quadratic function, so we know it'll have that parabola shape.
Do you know about parent functions and shifting?  We could look at this with the parent function y=x^2 rotated about the x-axis and compressed, with the second being shifted vertically 4 units.  Otherwise, we could just plot a few points on a graph and see visually how it works out.

anonymous · Answer

I haven't heard of parent functions and shifting but I think I understand what you're talking about.

anonymous · Answer

but how do i know where to graph the points?

accessdenied · Answer

we can just choose x-values and evaluate each function for the y-values
there isn't necessarily a 'wrong' x-value to choose, just need about 5 that are on our graph, easiest being x:={-2,-1,0,1,2}

anonymous · Answer

so then i just put those in  and find some points to plot and then compare the different graphs?

accessdenied · Answer

yeah, here's how I graphed the first function (in red)
 the same can be done to the second function as well to get the second function's graph

anonymous · Answer

flutter you

anonymous · Answer

Fu c k you