- Data Structure
- Networking
- RDBMS
- Operating System
- Java
- MS Excel
- iOS
- HTML
- CSS
- Android
- Python
- C Programming
- C++
- C#
- MongoDB
- MySQL
- Javascript
- PHP
- Physics
- Chemistry
- Biology
- Mathematics
- English
- Economics
- Psychology
- Social Studies
- Fashion Studies
- Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
If the polynomials $2x^3 + ax^2 + 3x - 5$ and $x^3 + x^2 - 4x + a$ leave the same remainder when divided by $x - 2$, find the value of $a$.
Given:
The polynomials $2x^3 + ax^2 + 3x - 5$ and $x^3 + x^2 - 4x + a$ leave the same remainder when divided by $x - 2$.
To do:
We have to find the value of $a$.
Solution:
The remainder theorem states that when a polynomial, $p(x)$ is divided by a linear polynomial, $x - a$ the remainder of that division will be equivalent to $p(a)$.
Let $f(x) = 2x^3 + ax^2 + 3x - 5$ and $g(x) = x^3 + x^2 - 4x + a$
$p(x) = x-2$
So, the remainders will be $f(2)$ and $g(2)$.
$f(2) = 2(2)^3+a(2)^2+3(2) -5$
$= 2(8) + a(4) +6-5$
$=16+4a+1$
$=4a+17$
$g(2) = (2)^3+(2)^2-4(2) +a$
$= 8 + 4 -8 +a$
$=4+a$
This implies,
$4a+17=4+a$
$4a-a=4-17$
$3a=-13$
$a=\frac{-13}{3}$
Therefore, the value of $a$ is $\frac{-13}{3}$.
Advertisements