How do you divide (i+12) / (9i-10)i+129i10 in trigonometric form?

1 Answer
Apr 3, 2017

Use (r_1(cos(theta_1)+isin(theta_1)))/(r_2(cos(theta_2)+isin(theta_2))) = r_1/r_2(cos(theta_1-theta_2)+isin(theta_1-theta_2))r1(cos(θ1)+isin(θ1))r2(cos(θ2)+isin(θ2))=r1r2(cos(θ1θ2)+isin(θ1θ2))

Explanation:

Compute r_1r1:

r_1 = sqrt(12^2+1^2)r1=122+12

r_1 = sqrt(145)r1=145

Compute theta_1θ1

theta_1 = tan^-1(1/12)θ1=tan1(112)

Compute r_2r2:

r_2 = sqrt(-10^2+9^2)r2=102+92

r_2 = sqrt(181)r2=181

Compute theta_2θ2 (second quadrant)

theta_2 = tan^-1(9/-10)+piθ2=tan1(910)+π

The resulting division is:

sqrt(145/181)(cos(tan^-1(1/12)-tan^-1(9/-10)-pi)+isin(tan^-1(1/12)-tan^-1(9/-10)-pi))145181(cos(tan1(112)tan1(910)π)+isin(tan1(112)tan1(910)π))