How do you find the vertex and axis of symmetry, and then graph the parabola given by: #y= -2x^2#?

Answer 1

Vertex: #(0,0)#
Axis of symmetry: #x=0#
(See below for graph)

#y=-2x^2# and be re-written in explicit vertex form as #y= (-2)(x-color(red)(0))^2 + color(blue)(0)# #color(white)("XXX")#with vertex at #(color(red)(0),color(blue)(0))#
Any parabola with the form: #color(white)("XXX")y=ax^2+bx+c# has a vertical axis of symmetry (through the vertex) and opens upward if #a > 0# or downward if #a < 0# Therefore the axis of symmetry for #y=-2x^2 (+0x+0)# is #x=0# (and opens downward).
Note that #color(white)("XXX")#x-intercept (value of #x# when #y=0#) is #0# and #color(white)("XXX")#y-intercept (value of #y# when #x=0#) is #0# so #color(white)("XXX")#the x and y intercepts do not give use any additional point to help us plot the graph. Therefore it will be necessary to pick a few other values for #x# and evaluate their corresponding #y# values in order to plot the graph.

#{: (x,,y), (0,,0), (-1,,-2), (+1,,-2), (-2,,-8), (+2,,-8) :}#

Plotting these point-pairs on the Cartesian plane ought to allow us to draw the function's graph.

(Sadly, it appears that Socratic.org is currently experiencing a bug that prevents posting a graph. I will attempt to check again later and add the graph if possible).

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Answer 2

The vertex of the parabola given by (y = -2x^2) is at the point (0, 0), and the axis of symmetry is the vertical line x = 0. To graph the parabola, you plot the vertex at (0, 0) and then use the symmetry of the parabola to plot additional points symmetrically on both sides of the axis of symmetry. The parabola opens downwards because of the coefficient -2 in front of (x^2).

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.

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