Answer:
225
Step-by-step explanation:
Using the basic components of summation ∑
∑n = n(n + 1) and ∑1 = n
Thus
∑ (2n - 1) ← for n = 1 to 15
= ∑2n - ∑1
= 2∑n - ∑1
= 2 ( n(n + 1)) - n
= n(n + 1) - n ← Evaluate for n = 15 ( the upper value )
= 15 × 16 - 15
= 240 - 15
= 225
Answer:
16.9 units
Step-by-step explanation:
Sometimes the easiest way to work these problems is to get a little help from technology. The GeoGebra program/app can tell you the length of a "polyline", but it takes an extra segment to complete the perimeter. It shows the perimeter to be ...
14.87 + 2 = 16.87 ≈ 16.9 . . . units
_____
The distance formula can be used to find the lengths of individual segments. It tells you ...
d = √((Δx)² +(Δy)²)
where Δx and Δy are the differences between x- and y-coordinates of the segment end points.
If the segments are labeled A, B, C, D, E in order, the distances are ...
AB = √(5²+1²) = √26 ≈ 5.099
BC = √(1²+3²) = √10 ≈ 3.162
CD = Δx = 3
DE = √(3²+2²) = √13 ≈ 3.606
EA = Δy = 2
Then the perimeter is ...
P = AB +BC +CD +DE +EA = 5.099 +3.162 +3 +3.606 +2 = 16.867
P ≈ 16.9
