Question

cos(x+y)/cos(x-y) = cotx-tany/cot x+tan y

​

Answer 1

Answer:

Explanation:

cos

(

x

−

y

)

cos

(

x

+

y

)

=

cos

x

⋅

cos

y

+

sin

x

⋅

sin

y

cos

x

⋅

cos

y

−

sin

x

⋅

sin

y

=

cos

x

⋅

cos

y

+

sin

x

⋅

sin

y

sin

x

⋅

cos

y

cos

x

⋅

cos

y

−

sin

x

⋅

sin

y

sin

x

⋅

cos

y

=

cos

x

⋅

cos

y

sin

x

⋅

cos

y

+

sin

x

⋅

sin

y

sin

x

⋅

cos

y

cos

x

⋅

cos

y

sin

x

⋅

cos

y

−

sin

x

⋅

sin

y

sin

x

⋅

cos

y

=

cos

x

⋅

cos

y

sin

x

⋅

cos

y

+

sin

x

⋅

sin

y

sin

x

⋅

cos

y

cos

x

⋅

cos

y

sin

x

⋅

cos

y

−

sin

x

⋅

sin

y

sin

x

⋅

cos

y

=

cot

x

+

tan

y

cot

x

−

tan

y