Question

if the value of sin(x+y)sin(x-y)+ sin(y+z)sin(y-z)+sin(z+x)sin(z-x) ​

Answer 1

Answer:

sin(x+y)sin(x-y)+sin(y+z)sin(y-z)+sin(z+x)sin(z-x)

=sin²x-sin²y+sin²y-sin²z+sin²z-sin²x

=0