Question

Please help! Perform the indicated operations in the following problem;
leave the answer in the rectangular form a + b i.
Simplify: 7i^2+8i^3+9i^4+10i^5
a. 16+2i
b. 2+2i
c. 16+18i
d. 2+18i

Answer 1

i^2=-1,i^3=-i,i^4=1,i^5=i
Therefor,-7-8i+9+10i=2+2i

Answer 2

just use fact that i^2 = -1

Answer 3

Thanks guys :)