## Trigonometry (11th Edition) Clone

$3.0642+2.5712i$
$4$ cis $40^{\circ}$=$4(\cos40^{\circ}+i\sin40^{\circ})$ Using a calculator, we find that $\cos40^{\circ}=0.76604$ and $\sin40^{\circ}=0.64279$ Substituting these values in the expression and solving: $4(\cos40^{\circ}+i\sin40^{\circ})=4(0.76604+0.64279i)=3.0642+2.5712i$