If A=1+j2 and B+2-J3, Find by calculation the magnitude and argument of the following complex numbers, stating each result in polar form: (i) A+B = (1+j2) + (2-j3) Is this where I cross multiply with first brackets and 2nd brackets....so 1 x 2 + 2 x6 2x2 +2 x 6 to get my answer I also have A - B , A x B , A/B
Adding real and complex numbers together is like adding apples and oranges. Therefore, it is impossible to add terms such as 1 and j2 or 2 and -j3. However, you can add terms of the same sort together the way Papabravo showed.
Yes. If A = a+bi and B = c+di, then A+B = (a+c) + (b+d)i. Note: I'm using the notation for complex numbers that I'm used to (a+bi), rather than a+bj. Khan Academy has some relevant videos on the complex plane that you might find helpful: https://www.khanacademy.org/math/precalculus/imaginary_complex_precalc/complex_num_precalc/
This looks like homework. Is it. If so, it is better placed in the Homework Help forum where it will get more attention than in the Math forum. If it's homework, I can move it.
What is the course? Are you supposed to just be learning about complex numbers, or are you supposed to already be familiar with them at this point? If the latter, then you will really need to look at some of those resources that have been linked in your various threads.
I have no idea what that course entails and what the prerequisites are. So is it assumed that you have never seen complex numbers before taking this course or not?
I didn't assume anything, I asked about what assumption the course makes regarding your prior knowledge of complex numbers. And since the question was duel ended (the "or not" at the end), it doesn't have a "yes" or "no" answer. So let me make it a yes or no question. Is this course taught based on the assumption that the students have never seen complex numbers before?
Here j2 and j3 are not the names of two identifiers. It is j·2 and j·3 where j is the imaginary constant. So (j2 - j3) = -j1. Personally I prefer putting the imaginary constant after the coefficient, but that's a matter of style.
Still, you should be able to explain why you did what you did based on your present understanding of the material. Otherwise you are just mimicking a monkey that is mimicking the instructor.
To show you what I mean, you should be able to apply normal algebra skills to factor out the j (remember, it's just a constant!) (1 + 2) + (j2 - j3) = (1 + 2) + j(2 - 3) = 3 + j(-1) = 3 - j1 Use that same process for (1+2) - (j2 - j3)