Calculating cos-1 ( is gladly appreciated : ) )

(Assuming you want your answer in radians)

If you want the answer in degrees just multiply your answer in radians by giving you:

.

We can do this since (half the circumference of the unit circle is equivalent to 180 degree rotation).

Step-by-step explanation:

is going to output an angle measurement in .

So we are looking to solve the following equation in that interval:

.

This happens in the second quadrant on the given interval.

The solution to the equation is .

So we are saying that implies since .

Answer is .

introduction, methodology, results, discussion

step-by-step explanation:

an observational study is one which consists of actual observation to record data and then analyse the data.

there are a number of factors that should be analyzed before starting an observational study.

the main four factors are:

i) introduction:   this should be analysed to check whether the purpose of the study is correctly established and the data recorded are appropriate for the study

methodology:   the method of collecting the data, such as whether randomly selected, and whether sample size matches with the population to be studied, whether questions asked are easy to answer by common men, etc.

results: then results such as summary of data with comments should be studied thoroughly

discussion:   the last is the discussion, this can be either by management people or persons who are all interested , etc.

answer: give more info

step-by-step explanation: