SOLUTION: Help is urgently needed. Find the remainder when x^100 + 2x^99 +3x^98 +... 100x is divided by {{{ x-1 }}}

Algebra.Com
Question 995916: Help is urgently needed.
Find the remainder when x^100 + 2x^99 +3x^98 +... 100x is divided by

Found 2 solutions by Boreal, ikleyn:
Answer by Boreal(15235)   (Show Source): You can put this solution on YOUR website!
synthetic division
1/1+2+3+4+5...
=1+1
===3 +3
======
=====6 +4
The first four terms are
x^99+3x^98+6x^97+10x^96+...
The coefficient of each term is the sum of all the preceding terms plus the coefficient of the next term.
The pattern will be 15,21,28,36.45.55.....
The coefficient of the 100th term is the sum of the preceding 99 terms plus the coefficient of the 100th term (100), so the quotient will be dividing x-1 into 4950x+100x or 5050 x.
That will go in 5050 times, and we subtract 5050x-5050, so that the remainder is 5050.

Answer by ikleyn(52814)   (Show Source): You can put this solution on YOUR website!
.
The  remainder theorem  says  (see the lesson Divisibility of polynomial f(x) by binomial x-a  in this site)  that the remainder of division the polynomial    by
the binomial    is equal to the value    of the polynomial.

By applying this theorem to the given polynomial f(x) = , it means that the remainder from division the polynomial by    is equal
to the value    of the polynomial.

In turn, this value is

f(1) = = 1 + 2 + 3 + . . . + 100.

It is the sum of first  100  natural numbers = sum of  100  terms of the arithmetic progression with the first term  1  and the common difference  1.

This sum is equal to   = 50*101 = 5050.

So,  the required remainder is 5050.


RELATED QUESTIONS

find the remainder when polynomial 3x^100+5x^85-4x^38+2x^17-6 is divided by... (answered by stanbon)
Find the remainder when f(x) = 3x³-2x²+x-1 is divided by... (answered by Boreal,ikleyn)
Find the remainder when P(x)=x^2+3x-2 is divided by D(x)=2x-1 (answered by josgarithmetic)
Find the remainder if the polynomial 3x^100+5x^95-4x^38+2x^17 is divided by... (answered by ikleyn)
please help me urgently.... 1)Find m and n if (x-2) and (x+3) are both factors of... (answered by KMST)
when a polynomial f(x) is divided by (x-3) the remainder is -9 and when divided by... (answered by robertb)
When a polynomial f(x) is divided by x-3 the remainder is -9 and when divided by 2x-1 the (answered by MathLover1,ikleyn)
a polynomial f(x) with rational coefficients leaves remainder 15 when divided by x-3 and... (answered by KMST)
Find the remainder when {{{3x^100+5x^85-4x^38+2x^17-6}}} is divide by... (answered by RAY100)