# Help needed

Found 27th Aug 2009
Can anyone answer these 2 quiz questions please??

thanks

1. Add the following sum of complex numbers, (0.13 - j0.27) + (0.13 - j0.27) + (0.15 - j0.09)?

11. The answer in question 1 is given in rectangular form. Can you give it in polar form?

...um...no....

jasonodell;6133100

...um...no....

...um ... urm ... no :w00t:

i feel a headache coming on just looking at it

i would try but i fear i may spontaniously combust if i do, so i wont :lol:

Original Poster

i havent the slighest idea of where to start....

this part of physics?

Original Poster

its called j notation

Not done this in a while so not sure if it's correct:

1) Treat real and imaginary parts separately:

(0.13+0.13+0.15) +(-0.27+(-0.27)+(-0.09))j = 0.41 - 0.63j = z

2) To put into polar form:
Find modulus of z (i.e. square root of ((0.41)^2 + (-0.63)^2) = 0.75

Find the argument of z (drawing it into quadrants may help). As real is positive and imaginary neative, it should be in 4th quadrant.

Therefore Arg(z)= tan inverse (0.63/0.41) = 56.9 degrees

Therefore polar form = 0.75(cos(56.9) + i sin(56.9)) --- You might want to convert degrees to radians.

I denoted imaginary parts as i rather than j.

Original Poster

thank you repped

calico_cat;6133400

Not done this in a while so not sure if it's correct:1) Treat real and … Not done this in a while so not sure if it's correct:1) Treat real and imaginary parts separately:(0.13+0.13+0.15) +(-0.27+(-0.27)+(-0.09))j = 0.41 - 0.63j = z2) To put into polar form:Find modulus of z (i.e. square root of ((0.41)^2 + (-0.63)^2) = 0.75Find the argument of z (drawing it into quadrants may help). As real is positive and imaginary neative, it should be in 4th quadrant. Therefore Arg(z)= tan inverse (0.63/0.41) = 56.9 degreesTherefore polar form = 0.75(cos(56.9) + i sin(56.9)) --- You might want to convert degrees to radians.I denoted imaginary parts as i rather than j.

Blimey ...simple as that !! :thinking:

queenlush;6133513

Blimey ...simple as that !! :thinking:

Easy as pi (3.14159........)
:-D

i swear maths stopped becoming maths past 5 years old...

i got 24jj

I got 38DD :-D

calico_cat;6133533

Easy as pi (3.14159........):-D

Ooooh tres drole