conver 4 < 30degrees and 7 < -145degrees into x+iy form correct to 4 significant figures.

Question

The above question is about complex numbers.

Answer 1

Let x=rcosø and y=rsinø, then the complex number x+iy becomes rcosø+isinø.

Now put ø=30 and r=4, and r=7 and ø=-145.

So we have x=4cos30=2√3=3.4641 and y=4sin30=2.

The first complex number is 3.464+2i, represented in an Argand diagram by the point (3.464,2).

The second complex number is 7cos(-145)+7isin(-145)=-5.734-4.015i or (-5.734,-4.015).

I don't know if this is what the question is asking for, but I nevertheless submit this answer.