We have to find the domain of y = cotx
We know that cotx = cos
x / sinx
And also when sinx becomes zero cotx becomes undefined
And again we know that value of cosx and sinx can be between -1 to 1
But value of cotx can lie in between -∞ to +∞
Just for example cot30 is cos30 / sin30
= √3/2/1/2 = √3
Therefore domain of cotx is x
x ∈ R , x ≠ πn for any integer n
hopefully this helps you and gives you insight in how to solve the problems from now on (:
= $11.8 + (2012-1997)([$11.8-$7.4][1997-1990])
= $11.8 + 5 ($4.4/7)
= $11.8 4/5 + $22/7
= $59/5 + $22/7
= $413/35 + $110/35
= $523/35 or $14 33/35
answer : SALES IN 2012 WOULD BE $14 33/35 BILLION OR $14.9 3/7
5/7 is a fraction in simplest form. To simplify a fraction, you always have to divide the numerator and denominator by the same number other than 1. Since 5 and 7 are only divisible by 1, 5/7 is the simplest form of the fraction.
Hope this helps.
Answer:
Test: 
< 20 with normal distⁿ
Hypothesis test:
H0: 
20 (Null Hypothesis, H₀ : = 20 is also correct)
H1: < 20 (Alternative Hypothesis, also called H₁)
This is lower tailed test.
Since sample is large, sample standard deviation can be taken as an approximation of population standard deviation.
x = 19.3
= 11.1
n = 444
significance level, 
= 0.05 (If no value is given, we take level of 0.05)
Test statistic 
= - 1.33
The attached files contains additional information
