Question

Prove that z=cosA+isinA

Answer 1

i have solved this question in my answers to prove that e^iπ+1=0 plz find there and plz mark brainliest

Answer 2

Suppose z = cosa + i sina

prove that 1/z = cosa - i sina

Remember that cos²θ+sin²θ = 1

1/z

= 1/(cos(a) + i.sin(a))

= (cos(a) - i.sin(a)) / [(cos(a) + i.sin(a))(cos(a) + i.sin(a))]

= (cos(a) - i.sin(a)) / (cos²(a) - i².sin²(a))

= (cos(a) - i.sin(a)) / (cos²(a) + sin²(a))

= (cos(a) - i.sin(a)) / 1

= cos(a) - i.sin(a)..

Hope It helps you