How do you perform the operation in trigonometric form $(5/3(cos(140)+isin(140)))(2/3(cos(60)+isin(60)))$ ?

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Answer 1 · 2016-12-20T17:23:48

$(5/3(cos140^@+isin140^@))(2/3(cos60^@+isin60^@))=10/9(cos200^@+isin200^@)$

$(5/3(cos140^@+isin140^@))(2/3(cos60^@+isin60^@))$

= $10/9[cos140^@cos60^@+icos140^@sin60^@+isin140^@cos60^@+i^2sin140^@sin60^@]$

= $10/9(cos140^@cos60^@-sin140^@sin60^@+icos140^@sin60^@+isin140^@cos60^@]$

= $10/9(cos(140^@+60^@)+isin(140^@+60^@))$

= $10/9(cos200^@+isin200^@)$

How do you perform the operation in trigonometric form (5/3(cos(140)+isin(140)))(2/3(cos(60)+isin(60)))(5/3(cos(140)+isin(140)))(2/3(cos(60)+isin(60)))?