163k views
5 votes

(4i)/(3+i)

User Arabam
by
3.0k points

1 Answer

4 votes

Answer:

(2 (3 i + 1))/5

Explanation:

Simplify the following:

(4 i)/(i + 3)

Multiply numerator and denominator of (4 i)/(i + 3) by 3 - i:

(4 i (-i + 3))/((i + 3) (-i + 3))

(3 + i) (3 - i) = 3×3 + 3 (-i) + i×3 + i (-i) = 9 - 3 i + 3 i + 1 = 10:

(4 i (-i + 3))/10

The gcd of 4 and 10 is 2, so (4 i (-i + 3))/10 = ((2×2) i (-i + 3))/(2×5) = 2/2×(2 i (-i + 3))/5 = (2 i (-i + 3))/5:

(2 i (-i + 3))/5

i (3 - i) = 1 + 3 i:

Answer: (2 (3 i + 1))/5

User Duru Cynthia Udoka
by
3.2k points