SOLUTION: The path of a baseball is given by {{{ f(x) = .0032x^2+x+3 }}}; where f(x) is the height, in feet, of the baseball and x is the horizontal distance, in feet, from the home plate.

Algebra ->  Expressions-with-variables -> SOLUTION: The path of a baseball is given by {{{ f(x) = .0032x^2+x+3 }}}; where f(x) is the height, in feet, of the baseball and x is the horizontal distance, in feet, from the home plate.       Log On


   



Question 446820: The path of a baseball is given by +f%28x%29+=+.0032x%5E2%2Bx%2B3+; where f(x) is the height, in feet, of the baseball and x is the horizontal distance, in feet, from the home plate.
a) How far from home plate is the ball when it hits the ground?
b) What is the height of the ball as it passes over the pitcher's mound, which is about 64 ft. from home plate?
c) What is the maximum height of the baseball?
All I'm really asking is how do I set up these problems, and, how do I get rid of that .0032? It's really throwing me off! lol

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Here's a plot of your equation:
+graph%28+400%2C+400%2C+-100%2C+100%2C+-100%2C+100%2C+.0032x%5E2+%2B+x+%2B+3%29+
As you can see, it makes no sense at all. The ball just keeps gaining
altitude like a space shot.
I think the equation should be:
+f%28x%29+=+-.0032x%5E2+%2B+x+%2B+3+ The first term rpresents the downward pull of gravity
Here's the plot4
+graph%28+500%2C+500%2C+-100%2C+380%2C+-100%2C+100%2C-+.0032x%5E2+%2B+x+%2B+3%29+
This makes a lot more sense
The ball hits the ground when +f%28x%29+=+0+
+-.0032x%5E2+%2B+x+%2B+3+=+0+
Use the quadratic formula:
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
+a+=+-.0032+
+b+=+1+
+c+=+3+
x+=+%28-1+%2B-+sqrt%28+1+-+4%2A%28-.0032%29%2A3+%29%29%2F%282%2A%28-.0032%29%29+
x+=+%28-1+%2B-+sqrt%28+1+%2B+.0384+%29%29%2F%28-.0064%29+
x+=+%28-1+-+1.019%29%2F%28-.0064%29+ (note that only the (-) square root makes sense)
+x+=+-2.019+%2F+-.0064+
+x+=+315.47+
The ball is 315.47 ft from home plate when it lands.
This is confirmed by the graph