Let S be the sum,
S = 2 + 4 + 6 + ... + 2 (n - 2) + 2 (n - 1) + 2n
Reverse the order of terms:
S = 2n + 2 (n - 1) + 2 (n - 2) + ... + 6 + 4 + 2
Add up terms in the same positions, so that twice the sum is
2S = (2n + 2) + (2n + 2) + (2n + 2) + ... + (2n + 2)
or
2S = n (2n + 2)
Divide both sides by 2 to solve for S :
S = n (n + 1)
Answer:
This the answer but it words because i didn't really wanna type all those numbers but just transfer this into numbers and you'll have the simplified version :)
x to the 4 power minus 4x to the third power minus 2x squared plus 12x plus 9
Step-by-step explanation:
Answer:
87.8 square meters
Step-by-step explanation:
First of all, find the area of the three recthangles.They are all 9m long and 3m wide. 9*3 is 27, and since there are three of them, 27*3 is 81.
To find the area of the two triangles, you could do 3*2.6. Normally, you would halve the values because they are triangles but since there's two of them it cancels out.
3*2.6 is 7.8, and adding that to the area of the rectangles gets the equation 81+7.8 which comes out to 87.8 square meters.
9514 1404 393
Answer:
207.24 in²
Step-by-step explanation:
The "r" in the formula stands for the radius of the cylinder. That is half the diameter, so is 3 in. The "h" in the formula stands for the cylinder height, shown as 8 in. Put these values in the formula and do the arithmetic.
SA = 2πr(r +h) = 2(3.14)(3 in)(3 in + 8 in) = 6.28(33 in²)
SA = 207.24 in²
The answer would be 1, since 7.24 is closer to 7
