Question

निम्नलिखित को सिद्ध कीजिए: cos(π\4-x)cos (π\4-y)-sin(π\4-x)sin(π\4-x)=sin(x+y)​

Answer 1

Step-by-step explanation:

Given cos(π\4-x)cos (π\4-y)-sin(π\4-x)sin(π\4-x)

= cos ( π\4-x + π\4-y )

= cos ( π\2-(x+y))

= sin(x+y)

cos(π\4-x)cos (π\4-y)-sin(π\4-x)sin(π\4-x)=sin(x+y)