How do you add (-8+4i)(8+4i) and (-3-3i)(33i) in trigonometric form?

1 Answer

sqrt(122)[cos(tan^-1(1/(-11)))+isin(tan^-1(1/(-11)))]" " "122[cos(tan1(111))+isin(tan1(111))] OR
sqrt(122)[cos(174.806^@)+isin(174.806^@)]" " "122[cos(174.806)+isin(174.806)]

Explanation:

Add (-8+4i)(8+4i) and (-3-3i)(33i) to obtain

-11+i11+i

Use the formula

a+bi=sqrt(a^2+b^2)[cos(tan^-1 (b/a))+i*sin(tan^-1 (b/a)]a+bi=a2+b2[cos(tan1(ba))+isin(tan1(ba)]

Let a=-11a=11 and b=1b=1

magnitude" " " "r=sqrt(a^2+b^2)=sqrt((-11)^2+1^2)=sqrt122 r=a2+b2=(11)2+12=122

the angle theta=tan^-1 (1/(-11))=174.806^@θ=tan1(111)=174.806

sqrt(122)[cos(tan^-1(1/(-11)))+isin(tan^-1(1/(-11)))]" " "122[cos(tan1(111))+isin(tan1(111))] OR
sqrt(122)[cos(174.806^@)+isin(174.806^@)]" " "122[cos(174.806)+isin(174.806)]

have a nice day... from the Philippines..