if x2 + x + 1 is a factor of x4 + ax2 + b , then the values of a and b respectively are ???
Divide f(x) = x4 + ax2 + b by g(x) = x2 + x + 1.
Given, g(x) = x2 + x + 1 is a factor of f(x) = x4 + ax2 + b.
∴ Remainder = (1 – a) x + (b – a) = 0 = 0x + 0
Comparing coefficient of x and constant term on both sides, we have
1 – a = 0
⇒ a = 1
and b – a = 0
⇒ b = a
⇒ b = 1
Hence, the value of a is 1 and b is 1.