Write the complex number in rectangular form round to the nearest tenth?

4(cos 5/6 i sine 5/6)
You want to have an answer in the form a bi, where a and b are real numbers.



a = rcos and b = rsin



Here, r = 4 and = 5/6



.. a = 4cos(5/6) = 4(-(3)/2) = -2(3)



b = 4sin(5/6) = 4(1/2) = 2



.. 4(cos 5/6 i sine 5/6) = -2(3) 2i



Note: Instead of writing 4(cos 5/6 i sine 5/6), you can use the abbreviated version rcis, where the