Whats the mean, media, maximum,minimum,mode and range of 1,2,1,3,4

First put the numbers in order least to greatest. 
(1,1,2,3,4)
The mean is the average of the group of numbers.
Too find it you add all the numbers up and divide it by how many numbers there are.
In this case it would be 11 divided by 5 so the mean would be 

Median is just another word for middle. After putting the numbers in order, the number in the center of the group is the median, in this case it would be 2.

The maximum would just be the largest number which is self explantory (4)

The minimum would be the lowest number (1)

I was taught to see mode as the word "most". All you do is see which number occurs the most. If all the numbers only occur once, your answer would be "No mode"

It is that simple! The Range is the difference between the lowest and highest number. So all you have to do is subtract the maximum by the minimum. In this case it would be 4-1 = 3

Correct  cos(α - β) = 140/221

Step-by-step explanation:

cosα = ±√(1 - sin²α) => cosα = ±√(1 - (-5/13)²) = ±√(1 - (25/169)  

cosα = ±√(169 -25)/169 = ± √144/169

cosα = ± 12/13  since it is given that α (alpha) ends in the third quadrant

we choose  cosα = - 12/13

we know that is  tanβ = sinβ/cosβ = - 8/15 or sinβ : cosβ = 8 : 15 =>

sinβ = 8k and cosβ = 15k  where k is the coefficient of proportionality

we know the basic trigonometric equality

sin²β + cos²β = 1    when we replace the coefficients we get

(8k)² + (15k)² = 1 => 64k² + 225k² = 1 => 289k² = 1 => k² = 1/289 =>

k = 1/17   now we get sinβ and cosβ

since it is given that  β (beta) ends in the second quadrant

sinβ = 8/17 and cosβ = - 15/17

As we know it is:

cos(α - β) = cosα cosβ + sinα sinβ = - 12/13 · (- 15/17) + (- 5/13) · 8/17 =>

cos(α - β) = 180/221 - 40/221 = 140/221

cos(α - β) = 140/221

God is with you!!!