x cos A+ y cos B +z cos C=0
x sin A + y sin B + z sin C=0
x Sec A + y Sec B + z Sec C=0
prove that (x^2 + y^2 -z^2)^2= 4x^2y^2
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Answer:
Step-by-step explanation:
cotα
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
The correct option is C cotα.
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