Calculate a 1 4i b 1 i3 i2 3i c i1 4i33 2i2 d pi i
Solution
a) . first we have to make everyhting in the form of a+bi then we can find | a+ib| value
given
| (1+4i) / (-3 -i) |
the conjugate of -3-i is -3 +i
now divide and multiply with -3+i
| (1+4i) (-3+i) / (-3-i) (-3+i) | = | (-3+i -12i+4i^2) / (9 -i^2) |
= | (-3 -11i -4 / (9+1) | since (i^2 =-1)
= | -7 -11i/10) |
= sqrt(7^2 +11^2) /10
= sqrt(49 +121) /10
= sqrt(170)/10
b) . (1+i)\' . (3 -i) (2 -3i)
here (1+i)\' is the congugate of 1+i is 1-i
so (1-i) (3-i)(2-3i) = (1-i).(6-9i-2i+3)
=(1-i)(9-11i)
=(9-11i-9i+11)
= (20-20i)
| 20 -20i| = sqrt(400+400) = sqrt(800)
= 20 sqrt(2)
similerly we can solve remaining two
3). |
|i(1+4i)^3) / (-3-2i)^2 |
to solve this first we have to simplify
(1+4i)^3 and (-3 -2i)^2
(1+4i)^3 = 1 + 3 (4i) +3 (4i)^2 + (4i)^3
= 1 +12i +3 (-16) -64i
= 1 + 12i -48 -64i
= -47 -52i
(-3 -2i)^2 = 9 +(2i)^2 + 2.3.(2i)
= 9 -4 +12i
= 5 +12i
|i(1+4i)^3) / (-3-2i)^2 | = | i(-47 -52i) / (5+12i) |
= | (-47i +52) /(5+12i) |
= | (-47i+52)(5-12i) /(5+12i) (5-12i)|
= | (-235i -564+260-624i) / (25+144) |
= | (-859i -264)/169|
| (-859i -264)/169| = sqrt(859^2 +264^2)/169
= sqrt(737661 +69696)/169
= sqrt(807357)/169
| (pi +i)^96/ (pi-i)^96

