Answer:
- S7 = 175
- S17 = 2465
- Sn = 1/2(n³ +n)
Step-by-step explanation:
The progression of sums is ...
1, 5, 15, 34, 65, ...
So, first differences are ...
4, 10, 19, 31
Second differences are ...
6, 9, 12, ...
Third differences are constant:
3, 3, ...
This means the expression for Sn will be a cubic expression. If dn is the first of the n-th differences, then the equation can be written as ...
Sn = S1 +(n -1)(d1 +(n -2)/2(d2 +(n -3)/3(d3)))
And this simplifies a little bit to ...
Sn = 1 +(n -1)(4 +(n -2)(n +3)/2)
In simpler form, we have ...
Sn = 1/2(n³ +n)
Then the two terms we're interested in are ...
S7 = (1/2)(7³ +7) = 175
S17 = (1/2)(17³ +17) = 2465
Hello, there!
The LCM would most likely be:
So, go through all of your factors to find your
of those
~
Answer:
arc axb=4.938
Step-by-step explanation:
to find the measure of arc AXB find angle P first
length of the arc=rФ
in triangle APQ sin angle APQ= opp/hyp=AQ(radius)/PQ=5/√5+√21
in traingle PQB sin angle BPQ= opp/hyp.=5/√5+√21
angle P"
2arcsin 5/√5+√21= 94.324 degrees=(π*94.324)/180=1.64626 rad.
arc AXB=Фr (Ф=94.324 , r=3)
arc axb=4.938
