Question

英文数学题，帮帮忙

Suppose the fench at left field is 5 feet high and 230 feet from home plate. Determine a new slope
velocity is 120 feet per second, so that the softball will clear the fench by just three foot.

formula= y= - 16（1＋s^2 ）*（x/v）^2＋sx＋4
s=slope
v=feet per second
y= height above the ground in feet
x= distance on the ground from home plate in feet

slope是多少
最后个问题。。y＝-16 (1+s^2)*(233/120)^2 + 233s +4 把230换成233 然后y＝0 那么slope的两个直是多少。。

Answer 1

公式不是直接给出来了么？
把各项的值代进去就行了啊。

v = 120 feet per second
y = 5 feet high
x = 230 feet from home plate

代进公式就是
5 = -16 (1+s^2)*(230/120)^2 + 230s +4

整理一下就是529s^2 - 2070s +538 =0
一元二次方程求根，两个根：3.63和0.28

slope有两个值，3.63或者0.28.....
不要问我物理意义啊，我只是套用公式。。。我没明白过来那个公式怎么来的呢。。。。

如果是233就是0 = -16 (1+s^2)*(233/120)^2 + 233s +4
整理一下 60.32s^2-233s+56.32=0
slope的两个值是 3.60和0.26