we can answer this problem asking to express the complex number -6i in trigonometric form. first thing to do is to evaluate the given expressions
cos 0 is 1 sin 0 is 0 sin 180 is 0 cos 180 is -1 cos 270 is 0 sin 270 is -1 sin 90 is 1 cos 90 is 0. Hence the answer to this problem is B.6(cos 270° + i sin 270°)