Answer:
Step-by-step explanation:
Since the sample size is quite large, we can use the z-distribution.
The margin of error is given by
Where n is the sample size, s is the sample standard deviation and is the z-score corresponding to a 90% confidence level.
The z-score corresponding to a 90% confidence level is
Significance level = α = 1 - 0.90= 0.10/2 = 0.05
From the z-table at α = 0.05
z-score = 1.645
Therefore, the margin of error is 0.776.
4) (a) For these problems, you should take time to familiarize yourself with common fractions that appear on the unit circle. does not appear in the unit circle unless you take the quotient 1/2 divided by sqrt(3)/2 which gives you 1/sqrt(3) which is the same as sqrt(3)/3. So our numerator is 1/2 and our denominator is sqrt(3)/2.
And remember tangent is just sin/cos. So what degree has sinx as 1/2 and and cosx as sqrt(3)/2? Well, 30 degrees does, but 30 degrees is not within the range we are given. That means they are looking for a sinx that gives us -1/2 and a cosx that gives us -sqrt(3)/2 and that is 210 degrees.
And 210 degrees in radians is 7pi/6.
I hoped that made sense.
(b) This is a lot easier. What angle gives us a cos x of -sqrt(3)/2? According to the unit circle, 150 degrees and 210 degrees does. They usually want these in radians, so the answer is 5pi/6 and 7pi/6, respectively.
5) What quadrant is radian measure 5 in?
Well 2pi or roughly 6.28 is a full circle. And 5 is slightly less than 6.28, so it is probably in quadrant IV.
But to be sure let's change 5 radian to degrees:
5 * 180/pi = 900/pi = 286.48 degrees
286.48 degrees is definitely in Q4, so we are correct.
Since the divisor is 2 digits, start by looking at the first 2 digits of the dividend. Those are 44, so you're dividing 44 by 15 at the first step. The quotient digit is the largest integer that gives a value less than or equal to the dividend (44) when multiplied by the divisor (15). For the first step, that digit is 2.
To find the new divisor, subtract the product of the divisor and the quotient digit (2·15=30) and bring down the next digit of the original dividend. Now, you have a dividend of 147 and a divisor of 15. Repeat the process as above.
The decimal point location in the answer can be found a number of ways. The simpliest is to put it above the decimal point in the dividend. (When the divisor is not an integer, multiply or divide both divisor and dividend by the same power of 10 until it is.)
