SOLUTION: Express the complex number in trigonometric form. -4

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Question 1133686: Express the complex number in trigonometric form.
-4
Found 2 solutions by MathLover1, Edwin McCravy:
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

Express the complex number in trigonometric form.
-4
z=r%28cos%28alpha%29%2Bi%2Asin%28alpha%29%29
-4=a-b%2Ai =>a=-4, b=0
r=sqrt%28%28-4%29%5E2%29
r=+sqrt%2816%29
r=4
z=4%2A+%28cos%28alpha%29%2Bi%2Asin%28alpha%29%29
tan%28alpha%29=0%2F-4=0
the angle of the point on the complex plane is pi.

z+=+4+%28cos%28pi%29+%2B+i+%2Asin%28pi%29%29

Answer by Edwin McCravy(20060) About Me  (Show Source):
You can put this solution on YOUR website!
We plot the point -4 = -4 + 0i which is the point (-4,0)



We draw the radius vector from the origin to the point (-4,0):



The length of the radius vector is r = 4 units.

We indicate the counter-clockwise angle q from the right side of the x-axis
around to the radius vector:



We determine from the graph that q = 180°

So



Edwin