Let f(x) be a polynomial. Find the remainder when f(x) is divided by x(x - 1)(x - 2), if f(0) = 0, f(1) = 1, and f(2) = 2.
You've presented a very similar problem to the last one, but with a slight change in the value of f(2). Let's work through it.
Understanding the Problem
f(x) is a polynomial.
f(0) = 0
f(1) = 1
f(2) = 2
We want to find the remainder when f(x) is divided by x(x - 1)(x - 2).
Using the Remainder Theorem
As before, we can write:
f(x) = q(x)x(x - 1)(x - 2) + r(x)
where q(x) is the quotient and r(x) is the remainder. Since the divisor is cubic, the remainder is at most quadratic:
r(x) = ax² + bx + c
Applying the Given Information
f(0) = 0:
0 = q(0) * 0 + a(0)² + b(0) + c
c = 0
f(1) = 1:
1 = q(1) * 0 + a(1)² + b(1) + c
1 = a + b + c
Since c = 0, we have a + b = 1
f(2) = 2:
2 = q(2) * 0 + a(2)² + b(2) + c
2 = 4a + 2b + c
Since c = 0, we have 4a + 2b = 2, which simplifies to 2a + b = 1
Solving for a and b
We have the system of equations:
a + b = 1
2a + b = 1
Subtract the first equation from the second equation:
(2a + b) - (a + b) = 1 - 1
a = 0
Substitute a = 0 into a + b = 1:
0 + b = 1
b = 1
The Remainder
We found:
a = 0
b = 1
c = 0
Therefore, the remainder r(x) is:
r(x) = 0x² + 1x + 0 = x
Conclusion
The remainder when f(x) is divided by x(x - 1)(x - 2) is x.