SOLUTION: Given that f(x)=(r+1)!/(r-1)! Simplified f(x) Evaluate the sum from 1to10of f(x)

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Question 1198571: Given that f(x)=(r+1)!/(r-1)!
Simplified f(x)
Evaluate the sum from 1to10of f(x)
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

Given that
f%28x%29=%28r%2B1%29%21%2F%28r-1%29%21
Simplify:
f%28x%29=%28r%2B1%29%21%2F%28r-1%29%21
cancel the factorials: n%21%2F%28n-m%29%21=n%28n-1%29*......*%28n-m%2B1%29, n%3Em
%28r%2B1%29%21%2F%28r-1%29%21=r%28r%2B1%29
siplified:
f%28x%29=r+%28r+%2B+1%29

Evaluate the sum from 1 to 10 of f%28x%29
f%281%29=1+%281%2B+1%29=2
f%282%29=2+%282%2B+1%29=6
f%283%29=3+%283%2B+1%29=12
f%284%29=4+%284%2B+1%29=20
f%285%29=5+%285%2B+1%29=30
f%286%29=6+%286%2B+1%29=42
f%287%29=7+%287%2B+1%29=56
f%288%29=8+%288%2B+1%29=72
f%289%29=9+%289%2B+1%29=90
f%2810%29=10+%2810%2B+1%29=110
the sum is;
2%2B6%2B12%2B20%2B30%2B42%2B56%2B72%2B90%2B110=440