At the time the rocket hits the ground h=0, given that h=-16t²+320t+32
when h=0, our equation will be:
-16t²+320t+32=0
solving the above by completing square method we proceed as follows;
-16t²+320t+32=0
divide though by -16 we get
t²-20t-2=0
t²-20t=2
but
c=(-b/2a)^2
c=(20/2)^2
c=100
hence:
t²-20t+100=100+2
(t-10)(t-10)=102
√(t-10)²=√102
t-10=√102
hence
t=10+/-√102
t~20.1 or -0.1
since it must have taken long, then the answer is 20.1 sec
Answer:
Height is 3
Step-by-step explanation:
4.24 x 4.24 x 6
Right triangle base = a + b + c
a^2 + 3^2 = 4.24^2
= a^2 + 9 = 17.98
We cross out b to subtract.
a^2 = 17.98 - 9
a^2 = 8.98
We then square √a^2 = √8.98
a = 2.996
We round up a = 3
We have found the height is 3
If there are real roots to be found for this polynomial, the Rational Root Theorem and synthetic division are the best way to find them. I teach from a book that uses c and d for the possible roots of the polynomial. C is our constant, 2, and d is the leading coefficient, 1. The factors of 2 are +/- 1 and +/-2. The factors for 1 are +/-1 only. Meaning, in all, there are 4 possibilities as roots for this polynomial. But there are only 3 total (because our polynomial is a third degree), so we have to find the first one, at least, from our possibilities above. Let's try x = -1, factor form (x + 1). If there is no remainder when we do the synthetic division, then -1 is a root. Put -1 outside the "box" and the coefficients from the polynomial inside: -1 (1 2 -1 -2). Bring down the first coefficient of 1 and multiply it by the -1 outside to get -1. Put that -1 up under the 2 and add to get 1. Multiply 1 times the -1 to get -1 and put that -1 up under the -1 and add to get -2. -1 times -2 is 2, and -2 + 2 = 0. So we have our first root of (x+1). The numbers we get when we do the addition along the way are the coefficients of our new polynomial, the depressed polynomial (NOT a sad one cuz it hates math, but a new polynomial that is one degree less than that of which we started!). The new polynomial is

. That can also be factored to find the remaining 2 roots. Use standard factoring to find that the other 2 solutions are (x+2) and (x-1). Our solutions then are x = -2, -1, 1, choice B from above.
Answer:
<h3>The option D) 1.50 is correct</h3><h3>That is the standard error of the sample mean is 1.50</h3>
Step-by-step explanation:
Given that a population that consists of 500 observations has a mean of 40 and a standard deviation of 15.
A sample size is 100 taken at random from the given population.
<h3>To find the standard error of the sample mean :</h3>
From the given Mean=40 and 
For N=100
<h3>The formula for standard error is

</h3>
Substitute the values in the above formula we get



∴ 
<h3>∴ The standard error of the sample mean is 1.50</h3><h3>Hence the option D) 1.50 is correct</h3>