Question

cos 10°-sin 70°\sin10°-cos 70°=​

Answer 1

Step-by-step explanation:

Given x−y=

3

1

....(1)

and cos

2

(πx)−sin

2

(πy)=

2

1

...(2)

⇒cosπ(x+y)cosπ(x−y)=

2

1

⇒cosπ(x+y)=1 (by (1))

⇒x+y=2n,n∈I.

Hope it helps☺