Question

Pre-Cal

Answer 1

http://assets.openstudy.com/updates/attachments/556f231ce4b0c4e453fa9e42-rosebud4612flvs-1433346859795-1.gif

Answer 2

@mathmate

Answer 3

the coefficient of x will be negative for a parabola that opens downwards
the function -x^2 is this shape with the vertex at the origin (0,0)
But we want to move this up to (0,36) by adding 36

so our equation would be

-x^2 + 36

Answer 4

Thanks! what about this part?
Create a table of values for a linear function. A drone is in the distance, flying upward in a straight line. It intersects the rainbow at two points. Choose the points where your drone intersects the parabola and create a table of at least four values for the function. Remember to include the two points of intersection in your table.

Answer 5

well we can choose one value that's on the y-axis say (0,20) for example.
Then one value on left side of our rainbow say x = -5 and y will then be -(-5^2) + 36 = 11

Answer 6

Ok!

Answer 7

we can then work out the equation of the line and find the point where it intersects another point on the curve and another point before or after the intersections

Answer 8

Don't we need to create a table w/ 2 intersection points too?

Answer 9

slope of line is (20-11)/ 0-(-5) = 9/5

Answer 10

yes we have one already and we can find the other by solving the 2 equations.

the line cuts the axis at y=20
so its equation is y = (9/5) x + 20

Answer 11

How would we do that? Just plug in points?

Answer 12

so another point could be at x = -7 and y= (9/5)*-7 + 20

Answer 13

to find the second point of intersection we need to solv
(9/5)x + 20 = -x^2 + 36

Answer 14

ok:)

Answer 15

would we subtract 20 from both sides?

Answer 16

its a quadratic so add x^2 to both sides
and subtract 36 from both sides

Answer 17

x^2 + (9/5)x - 16 = 0

Answer 18

now what do we do?

Answer 19

use the quadratic formula

Answer 20

Ok! But wouldn't the solution be complex making it no real solution?

Answer 21

no one solution will be negative though which you can ignore

Answer 22

the solution will be close to 3

so that will give you your 4 points

Answer 23

alrighty thank you!

Answer 24

yw