We know that : (a - b)(a + b) = a² - b²
We know that : 1 - sin²x = cos²x
We know that : sec²x = 1 + tan²x
Can you help me with 4 and 6 only? thank you
1 answer:
You might be interested in
Answer:
r =
Step-by-step explanation:
We simply are rearranging C= 2πr in terms of <em>r</em>. We just divide 2π on both sides.
Answer:
21
Step-by-step explanation:
Using<em> Simple Random Sampling</em>, we can estimate the sample size by the formula
where
n = sample size
Z = the z-score corresponding to the confidence level 99.5%
S = the assumed standard deviation = 3 seconds
e = margin of error = 2 seconds
<em>It is worth noticing that the higher the confidence level, the larger the sample should be. </em>
The z-score corresponding to a confidence level of 99.5% can be obtained either with a table or the computer and equals
Z = 3.023
Replacing the values in our formula
So the size of the sample should be at least 21.