It is asking you to find the sum of k^2 - 1 from k=1 to k=4. Since that is only 4 numbers, calculating the sum by hand wouldn’t be that bad.
(1^2 - 1) + (2^2 - 1) + (3^2 - 1) + (4^2 - 1) = 26
The easier way to find the sum is to use a few simple formulas.
When we have a term that is just a constant c, the formula is c*n.
When we have a variable k, the formula is k*n*(n+1)/2.
When we have a squared variable, the formula is k*n*(n+1)*(2n+1)/6.
In this case, we have a squared variable k^2 and a constant of -1.
So plug in n=4 to the formulas:
4*5*9/6 - 1*4 = 26
The answer is 26
Answer:
2, -3
Step-by-step explanation:
4 units down is -9, then a reflection over y axis makes -2 2 6 units up makes -9 -3
Answer:
For a data set of N elements:
{x₁, x₂, ..., xₙ}
The mean is:
The mean absolute deviation is:
And the population standard deviation is:
In this case, our set has 5 elements, and the set is:
{2, 4, 6, 9, 14}
The mean of this set is:
The mean absolute deviation is:
And the population standard deviation is:
0/9 = 0 and 3/0 = undefined. Any number divided by 0 is undefined, while 0 divided by any number is just 0.
