How do you multiply eπ4ieπ2i in trigonometric form?

1 Answer
Nov 4, 2016

eπ4ieπ2i=12+12i

Explanation:

As eπ4i=cos(π4)+isin(π4)

and eπ2i=cos(π2)+isin(π2)

eπ4ieπ2i

= (cos(π4)+isin(π4))(cos(π2)+isin(π2))

= cos(π2)cos(π4)+icos(π2)sin(π4)+isin(π2)cos(π4)+i2sin(π2)sin(π4)

= cos(π2)cos(π4)+i{cos(π2)sin(π4)}+sin(π2)cos(π4)sin(π2)sin(π4)

= {cos(π2)cos(π4)sin(π2)sin(π4)}+i{cos(π2)sin(π4)}+sin(π2)cos(π4)

= cos(π2+π4)+isin(π2+π4)

= cos(3π4)+isin(3π4)

= 12+12i