EFFECT OF COEFFICIENT OF X^2 ON PARABOLA SHAPE
Write-pair-share

Part 1
Consider the general form of a quadratic function,  

    or     ,    where a≠0.

1.	If a>0 and if the coefficient a is increased in value,  how will this increase affect the shape of the parabola?  For the sake of simplicity, you may assume that both b and c are fixed values and that b=1 and c=2.  

The shape of the resulting parabola will be:

CIRCLE ONE:     A.  NARROWER	      B.  SAME SHAPE 	C.  WIDER

CIRCLE ONE:     A.  OPENING UPWARD	      B.  OPENING DOWNWARD

2.	If a<0 and if the coefficient a becomes increasingly negative in value (i.e., as  increases while a remains negative), how will this increase affect the shape of the parabola?  For the sake of simplicity, you may assume that both b and c are fixed values and that b=1 and c=2.  

The shape of the resulting parabola will be:

CIRCLE ONE:     A.  NARROWER	      B.  SAME SHAPE 	C.  WIDER

CIRCLE ONE:     A.  OPENING UPWARD	      B.  OPENING DOWNWARD

After making your decision concerning the possible answer choices, please discuss your conjecture with your nearest neighbor and explain to each other the underlying reasoning.  You don’t necessarily have to agree with each other’s assessment, but do have a candid discussion; you are free to change your initial reasoning in light of your neighbor’s explanation

Part 2
Afterwards, please record your conjecture and reasoning in written form; a single paragraph will be sufficient.  

Part 3
Briefly describe  Please describe the key elements of your analysis.

1.	Do your calculations uphold your conjecture (from Parts 1 and 2) concerning the effect of increasing the value of a on the position of the vertex?  If not, please explain in more detail.