Question

1
If 2 cos a = x+-,2 cos ß = y +-
Cos B=y+1
х
y
1
1
2 cos y = 2 +- then xyz +
xyz
z​

Answer 1

Step-by-step explanation:

If cosx+cosy+cosα=0……(i)

sinx+siny+sinα=0……(ii)

then cot(

2

x+y

)=?

Now,

cosx+cosy=−cosα

2cos(

2

x+y

).cos(

2

x−y

)=−cosα……(iii)

sinx+siny=−sinα

2sin(

2

x+y

).cos(

2

x−y

)=−sinα……(iv)

By (iii)÷(iv)

2×sin(

2

x+y

).cos(

2

x−y

)

2×cos(

2

x+y

).cos(

2

x−y

)

=

−sinα

−cosα

⇒cot(

2

x+y

)=cotα