Question 1118430
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Please proofread your posts BEFORE sending.  It is extremely rude of you to make the tutors have to decipher your nonsensical post because you were simply too lazy to correct your typos.


<i>A&#8203; high-rise condominium building is 408 feet high. Suppose that a ball is projected upward from the top and its position s in feet above the ground is given by the equation s = &#8722;16t^2 + 80t + 408&#8203;, where t is the number of seconds elapsed. How long will it take for the ball to reach a height of 460 feet above the&#8203; ground?</i>


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ -16t^2\ +\ 80t\ +\ 408\ =\ 460]


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ -16t^2\ +\ 80t\ -\ 52\ =\ 0]


Solve the quadratic for *[tex \Large t].  Hint:  Divide the entire equation by 4 (to make the arithmetic simpler) and then use the Quadratic Formula.  Since the projectile will be at a height of 460 feet twice, once on the way up and once on the way down, you will have two real roots to this equation.  The way the question is worded, it is safe to assume that the smaller value of *[tex \Large t] is the desired answer.


*[illustration ProjectileFromCondo.jpg]


John
*[tex \LARGE e^{i\pi}\ +\ 1\ =\ 0]
My calculator said it, I believe it, that settles it
<img src="http://c0rk.blogs.com/gr0undzer0/darwin-fish.jpg">
*[tex \Large \ \
*[tex \LARGE \ \ \ \ \ \ \ \ \ \  
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