The value of (i5+i6+i7+i8+i9)(1+i)
12(1+i)
12(1−i)
1
12
i5+i6+i7+i8+i91+i=i−1−i+1+i1+i[As, i5=i,i6=−1,i7=−i,i8=1,i9=i]=ii+1=ii+1×i−1i−1=i(i−1)i2−1=i2−i2=12(1+i)