Prove trigonometric identites see picture for more instructions

[adrian.tuesta]

 

[Harry_the_cat]

Start by applying the identities for "sine of a sum" and "cosine of a difference" to the LHS.
Show us what you get.

 

[blamocur]

From https://www.freemathhelp.com/forum/threads/read-before-posting.109846/: Show your beginning work, or ask a specific question about the exercise, or explain why you're stuck.
A more legible writing would help too.

 

[Deleted member 4993]

View attachment 29699

Hint:
sin(x-y) = sin(x) * cos(y) - cos(x) * sin(y) ..........(Sine of difference).......... and

cos(x+y) = cos(x) * cos(y) - sin(x) * sin(y) ........(Cosine of summation) ....and

legible handwriting will help you in almost every aspect of education.