Guest

If x=cosA+ i sinA, y= cosB+ i sinB, z= cosG + i sinG and x+y+z=xyz, then prove that cos(B-G)+cos(G-A)+cos(A-B)=1

If x=cosA+ i sinA, y= cosB+ i sinB, z= cosG + i sinG and x+y+z=xyz, then prove that cos(B-G)+cos(G-A)+cos(A-B)=1

Question Image
Grade:12th pass

2 Answers

Saurabh Koranglekar
askIITians Faculty 10335 Points
4 years ago
576-1973_1.PNG
Vikas TU
14149 Points
3 years ago
Dear student 
by De Moivre's Theorem,
(cosa+cosb+cosc)+i(sina+sinb+sinc)=cos(a+b+c)+isin(a+b+c)
Equating real and imaginary parts,
cosa+cosb+cosc=cos(a+b+c)
and similarly for sine. Now,
(a−b)+(b−c)+(c−a)=0

Think You Can Provide A Better Answer ?

ASK QUESTION

Get your questions answered by the expert for free