Snap & Solve (Mathematics - Science)
math
a) use formula
1/2 ( sin (A+B) + sin (A-B) )
= 1/2 ( sin (2x + x ) + sin (2x - x) )
= 1/2 ( sin (3x) + sin (x) )
b) 1/2 ( cos (A+B) + cos (A-B) )
= 1/2 ( cos (5x) + cos (-3x) )
When cos (-x)= cos (x)
Thus , = 1/2 ( cos (5x) + cos (3x) )
C) -1/2 ( cos(A+B) - cos (A-B) )
= -2× -1/2 ( cos (4x ) - cos (2x) )
= - ( cos (4x ) + cos (2x) )