Question

15. JAGUARUNDI A jaguarundi springs from a fence post to swat at a low flying bird.

Her height h in feet can be modeled by the equation h = -161? + 22.31 + 2,

where t is time in seconds. Use the discriminant to determine if the jaguarundi

will reach the bird if the bird is flying at a height of 10 feet. Explain.

Answer 1

No, the Jaguarundi will not reach the bird

Explanation:

The equation is

`h=-16t^2+22.3t+2`

When h = 10 feet

`10=-16t^2+22.3t+2`

`\Rightarrow -16t^2+22.3t-8=0`

`a=-16`

`b=22.3`

`c=-8`

Discriminant is given by

`b^2-4ac=22.3^2-4(-16)(-8)`

`\Rightarrow b^2-4ac=-14.71`

`\Rightarrow b^2-4ac<0`

So, the Jaguanrundi will not reach the bird as the roots will be imaginary.

Answer 2

The discriminant, -14.71 < 0, shows that there is no solution of the equation, h = -16·t² + 22.3·t + 2, at the line 'h = 10' feet, therefore, the Jaguarundi height as she springs will not be up to 10 feet and therefore she will not reach the bird

Explanation:

From the question, the equation that models the Jaguarundi's height, 'h', ma be written approximately as follows;

h = -16·t² + 22.3·t + 2

Where;

t = The time (duration) in seconds

The discriminant of the equation a·x² + b·x + c = 0 is b² - 4·a·c

When h = 10, we have;

10 = -16·t² + 22.3·t + 2

∴ 0 = -16·t² + 22.3·t + 2 - 10 = -16·t² + 22.3·t - 8

The discriminant of the given quadratic equation is given as follows;

The discriminant = 22.3² - 4 × (-16 × (-8)) = -14.71 < 0

Therefore, the function, h = -16·t² + 22.3·t + 2 has no real root at h = 10

The parabola does not reach or pass through the line h = 10 which is the height at which the bird is flying.

The Jaguarundi will not reach the bird flying at the height of 10 feet.