Q. Given that 1−i is a zero of p(x)=x3−6x2+10x−8, find the remaining zeroes.
Identify Conjugate Pairs: Since complex roots of polynomials with real coefficients come in conjugate pairs, if 1−i is a zero, then its conjugate, 1+i, must also be a zero of p(x).
Find Product of Factors: We can use synthetic division or long division to divide the polynomial by (x−(1−i))(x−(1+i)) to find the remaining zero. First, let's find the product of these two factors.
Perform Polynomial Division: The product of (x−(1−i))(x−(1+i)) is (x−1+i)(x−1−i), which simplifies to (x−1)2−i2. Since i2=−1, this further simplifies to x2−2x+1−(−1), which is x2−2x+2.
Set Up Division: Now we divide the polynomial p(x) by x2−2x+2 using synthetic division or long division. We set up the division as follows:x3−6x2+10x−8÷(x2−2x+2)
Perform Division: Performing the division, we get:x−4 with a remainder of 0, since 1−i is indeed a root and its conjugate pair should also be a root, leaving us with a linear factor that gives the remaining real root.
Identify Remaining Zero: The quotient x−4 represents the linear factor of p(x) that gives the remaining real zero. Therefore, the remaining zero is x=4.