Answer:
Since time can't be negative, the only possible solution is 0.72 s.
Step-by-step explanation:
When the ball hits the ground its height is equal to 0, so we must find a value for "t" that results in h = 0. We have:
![-16*t^2 + 6*t + 4 = 0\\t_{1,2} = \frac{-6 \pm \sqrt{(6)^2 - 4*(-16)*(4)}}{2*(-16)}\\t_{1,2} = \frac{-6 \pm \sqrt{292}}{-32}\\t_{1,2} = \frac{-6 \pm 17.1}{-32}\\t_1 = \frac{-6 -17.1}{-32} = 0.72\\t_2 = \frac{-6 + 17.1}{-32} = -0.35\\](https://tex.z-dn.net/?f=-16%2At%5E2%20%2B%206%2At%20%2B%204%20%3D%200%5C%5Ct_%7B1%2C2%7D%20%3D%20%5Cfrac%7B-6%20%5Cpm%20%5Csqrt%7B%286%29%5E2%20-%204%2A%28-16%29%2A%284%29%7D%7D%7B2%2A%28-16%29%7D%5C%5Ct_%7B1%2C2%7D%20%3D%20%5Cfrac%7B-6%20%5Cpm%20%5Csqrt%7B292%7D%7D%7B-32%7D%5C%5Ct_%7B1%2C2%7D%20%3D%20%5Cfrac%7B-6%20%5Cpm%2017.1%7D%7B-32%7D%5C%5Ct_1%20%3D%20%5Cfrac%7B-6%20-17.1%7D%7B-32%7D%20%3D%200.72%5C%5Ct_2%20%3D%20%5Cfrac%7B-6%20%2B%2017.1%7D%7B-32%7D%20%3D%20-0.35%5C%5C)
Since time can't be negative, the only possible solution is 0.72 s.
Answer:
a) n = 100
![\bar{x} = 58](https://tex.z-dn.net/?f=%5Cbar%7Bx%7D%20%3D%2058)
s = 8
Confidence interval = 95%
Z at 95% = 1.96
Confidence interval formula :
to ![\bar{x}-z\frac{s}{\sqrt{n}}](https://tex.z-dn.net/?f=%5Cbar%7Bx%7D-z%5Cfrac%7Bs%7D%7B%5Csqrt%7Bn%7D%7D)
Substitute the values :
Confidence interval :
to ![58+1.96 \times \frac{8}{\sqrt{100}}](https://tex.z-dn.net/?f=58%2B1.96%20%5Ctimes%20%5Cfrac%7B8%7D%7B%5Csqrt%7B100%7D%7D)
Confidence interval :
to ![59.568](https://tex.z-dn.net/?f=59.568)
b)n = 200
![\bar{x} = 62](https://tex.z-dn.net/?f=%5Cbar%7Bx%7D%20%3D%2062)
s =11
Confidence interval = 90%
Z at 90% = 1.64
Confidence interval formula :
to ![\bar{x}-z\frac{s}{\sqrt{n}}](https://tex.z-dn.net/?f=%5Cbar%7Bx%7D-z%5Cfrac%7Bs%7D%7B%5Csqrt%7Bn%7D%7D)
Substitute the values :
Confidence interval :
to
Confidence interval :
to ![63.275](https://tex.z-dn.net/?f=63.275)
Answer:
0.02
Step-by-step explanation:
0.3/15=(0.3/3)/(15/3)=0.1/5=0.02
Answer:
Step-by-step explanation: X=2
Answer:
x = 1
Step-by-step explanation:
you can tell by 7x=7
divide 7 on both sides and get 1