First, let's simplify i12. We know that i2=−1, i3=−i, and i4=1. Thus, i12=(i4)3=13=1. Therefore, 0.5i12=0.5×1=0.5. Next, simplify the numerator (3i+1)(i−3): (3i+1)(i−3)=3i2−9i+i−3=3(−1)−8i−3=−3−8i−3=−6−8i. So, the expression becomes:
0.5+i−1−6−8i. To divide complex numbers, multiply the numerator and denominator by the conjugate of the denominator.
The conjugate of i−1 is −i−1. i−1−6−8i=(i−1)(−i−1)(−6−8i)(−i−1)=−i2−i+i+16i+6+8i2+8i=−(−1)+114i+6+8(−1)=1+114i+6−8=214i−2=7i−1. Therefore,
0.5+i−1−6−8i=0.5+(7i−1)=0.5+7i−1=−0.5+7i.