# How do you perform the operation in trigonometric form (3/4(cos(pi/3)+isin(pi/3))(4(cos((3pi)/4)+isin((3pi)/4))?

Jan 2, 2017

You multiply the magnitudes and add the angles: (A(cos(theta) + isin(theta))(B(cos(phi) +isin(phi))) = AB(cos(theta+phi) + isin(theta+phi))

#### Explanation:

Multiply the $\frac{3}{4}$ and the $4$:

$\frac{3}{4} 4 = 3$

$\frac{3 \pi}{4} + \frac{\pi}{3} = \frac{13 \pi}{12}$
$3 \left(\cos \left(\frac{13 \pi}{12}\right) + i \sin \left(\frac{13 \pi}{12}\right)\right)$