Answer:
69 seconds, or 1 minute and 9 seconds
Step-by-step explanation:
1/3
mark tom travis
tom travis mark
travis mark tom
how many boys 3
how many total 9
3/9 = 1/3
C. i hope this is correct
Answer:
sin
(
x/
2
) = -
√
3
/2
Take the inverse sine of both sides of the equation to extract x
from inside the sine.
x/
2
=
arcsin
(
−
√
3/
2
)
The exact value of arcsin
(
−
√
3
/2
) is −
π
/3
.
/x
2
=
−
π
/3
Multiply both sides of the equation by 2
.
2
⋅
x
/2
=
2
⋅
(
−
π
/3
)
Simplify both sides of the equation.
x
=
−
2
π
/3
The sine function is negative in the third and fourth quadrants. To find the second solution, subtract the solution from 2
π
, to find a reference angle. Next, add this reference angle to π to find the solution in the third quadrant.
x
/2
=
2
π
+
π/
3
+
π
Simplify the expression to find the second solution.
x
=
2
π
/3
4
π
Add 4
π to every negative angle to get positive angles.
x
=
10
π
/3
The period of the sin
(
x
/2
) function is 4
π so values will repeat every 4
π radians in both directions.
x
=2
π
/3
+
4
π
n
,
10
π/
3
+
4
π
n
, for any integer n
Exclude the solutions that do not make sin
(
x
/2
)
=
−
√
3/
2 true.
x
=
10
π
/3
+
4
π
n
, for any integer n
Answer:
Step-by-step explanation:
The geometric distribution represents "the number of failures before you get a success in a series of Bernoulli trials. This discrete probability distribution is represented by the probability density function:"
Let X the random variable that measures the number os trials until the first success, we know that X follows this distribution:
In order to find the expected value E(1/X) we need to find this sum:
Lets consider the following series:
And let's assume that this series is a power series with b a number between (0,1). If we apply integration of this series we have this:
(a)
On the last step we assume that 
and 
, then the integral on the left part of equation (a) would be 1. And we have:
And for the next step we have:
And with this we have the requiered proof.
And since 
we have that:
