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
<h3>
Answer: 75.36 square feet</h3>
Your teacher may want you to type the number only.
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Work Shown:
SA = surface area of a cylinder
SA = 2*pi*r^2 + 2*pi*r*h
SA = 2*3.14*2^2 + 2*3.14*2*4
SA = 75.36
The surface area is roughly 75.36 square feet.
Answer:
18.84 feet is the right answer
243 + 62-28 = n
243 + 34 = n
277 = n
n= 277
4/5 of 40 = 32
1/3 of 3 = 1
1/3 of 15 muffins = 10 muffins
