Write each complex number in rectangular form. Plot and label (with a - d) each point on the polar axes below.
let's use a) as an example 2(cos(135) + isin(135)) you basically just need to distribute the 2 to get 2cos(135) + 2i*sin(135), then replace cos(135) and sin(135) with their actual values (use a calculator)
2(cos(135) + isin(135)) = -1 + I sqrt 2
= -1 + i sqrt 2 *****
wait
hm 2*cos(135) = -2/sqrt(2) so -2/sqrt(2) + sqrt(2) * i should do it
(the coefficient sqrt(2) is written before the i)
i AM still getting the same answer
parentheses are important -1 + i sqrt 2 is not the same as [-1 + i]sqrt(2)
the one on top is the one written in standard form
Okay so it needs to include parentheses making the answer [-1 + i]sqrt(2)
solve that i get -1.41
you do not need to do anything with the coordinates once you have them -2/sqrt(2) + sqrt(2) * i is sufficient, nothing else needs to be done
similar thought process for b)
3cos(120) + 3i*sin(120), 3*cos(120)=-3/sqrt3
i think ;O
cos(120) = -1/2 so 3cos(120) = -3/2 don't forget about the 3*i*sin(120)
-3/2 3isqrt3/2
good so -3/2 + [3*sqrt(3)/2]i is your solution
cos(5pi/4) = -1/sqrt2 so 5cos(5pi/4) = -5/2 5*i*sin(5pi/4) = -5i/sqrt2
almost 5cos(5pi/4) = -5/sqrt(2) so your sol'n is -5/sqrt(2) + [-5/sqrt(2)]i
any attempts on d yet?
cos(5pi/3) = 1/2 so 4cos(5pi/3) = 2 4*i*sin(5pi/3) = -2i/sqrt3
good so 2 - (-2/sqrt(3))i
wait isn't it just -2sqrt(3) i
okay so c is cos(5pi/4) = -1/sqrt2 so 5cos(5pi/4) = -5/2 5*i*sin(5pi/4) = -5i/sqrt2 and d is cos(5pi/3) = 1/2 so 4cos(5pi/3) = 2 4*i*sin(5pi/3) = -2i/sqrt3i
you need to combine the values to get the complete coordinate c: -5/sqrt(2) + [-5/sqrt(2)]i d: 2 - 2sqrt(3) * i
those are your solutions
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