Find the remainder when x^51 is divided by x^2-3x+2.

+4 votes
530 views
asked Oct 16, 2016 in Mathematics by Rahul Roy (7,895 points) 33 108 286

1 Answer

+5 votes
answered Oct 16, 2016 by Abhishek Kumar (14,593 points) 5 9 35
selected Oct 17, 2016 by Rahul Roy
 
Best answer

Let p(x) = x 51 and q(x) = x – 3x + 2 = (– 1) (– 2)

When p(x) is divided by q(x), then by division algorithm there exists Q(x) and R(x) = ax+b such that 

x51 = Q(x)(x-1)(x-2) + ax +b where Q(x) is result and ax+b is remainder 
For x = 1 you get 
1^51 =
Q(1)(1-1)(1-2) + a+b then a+b = 1 
and 
2^51 =
Q(2)(2-1)(2-2) + 2a + b then 2a+b = 2^51 
Now solve 
a+b = 1 
2a+b = 2^51 
a = 2^(51) - 1 
b = 2- 2^(51) 
Remainder is x(2^51 - 1) + 2-2^51

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

One Thought Forever

“There is a close connection between getting up in the world and getting up in the morning.“
– Anon
~~~*****~~~

...