Question

Which of the quadratic functions has the narrowest graph?

y = −10x2



y=2/5x2

y = 9x2


y = −0.9x2

Answer 1

B. y=2/5x2. Hope this helps.

Answer 2

The quadratic functions which has the narrowest graph is:

`y=-10x^2`

Explanation:

For any quadratic function of the type:

`y=ax^2+bx+c`

if the modulus of a is the highest then the graph is narrowest.

and if modulus of a is smallest then the graph is widest.

a)

`y=-10x^2`

i.e.

`a=-10\\\\i.e.\\\\|a|=10`

b)

`y=(2)/(5)x^2`

i.e.

`a=(2)/(5)`

`|a|=(2)/(5)=0.4`

c)

`y=9x^2`

i.e.

`a=9`

i.e.

`|a|=9`

d)

`y=-0.9x^2`

i.e.

`a=-0.9`

i.e.

`|a|=0.9`

Since,

`|a|=10` is highest for the equation
`y=-10x^2`.

Hence, it has the narrowest graph.