Integrate by parts.
with
so that
where the last integral follows from
The answer is B because when u divide 35,4% by 100 =0.354
Square both given expressions and add them together. Make use of trig identities.
(sin(a) +sin(b))^2 = sin(a)^2 +2sin(a)sin(b) +sin(b)^2 = 5/3
(cos(a) +cos(b))^2 = cos(a)^2 +2cos(a)cos(b) +cos(b)^2 = 1
Adding, we have
sin(a)^2 +cos(a^2) +2(cos(a)cos(b) +sin(a)sin(b)) +sin(b)^2 +cos(b)^2 = 2 2/3
Of course, the first and last pairs of terms are 1 and 1, and the middle product is 2cos(a-b), so you have
1 + 2cos(a-b) +1 = 2 2/3
cos(a-b) = 1/3
Answer: a. n= 1068
b. n= 164
Step-by-step explanation:
The formula to find the sample size :
, where p=prior population proportion , z* = critical z-value and E = Margin of error.
Here , let p=proportion of computers that use a new operating system.
Given : Confidence level = 95%
i.e. z* = 1.96 [by z-table]
Margin of error : E = 3% =0.03
a. If p is unknown , then we assume p=0.5
Then,
i.e. n= 1068
b. p=0.96
Then,
i.e. n= 164.