#6) Sum of 2 Angles
var('y')
show(sin(x+y))
show(sin(x+y).simplify_trig())
show(plot3d(sin(x+y),(x,-2,2),(y,-2,2)),viewer='tachyon')
show(plot3d(sin(x)*cos(y)+sin(y)*cos(x),(x,-2,2),(y,-2,2)))
#7) Sum of 2 Angles
show(sin(x-y))
show(sin(x-y).simplify_trig())
show(plot3d(sin(x-y),(x,-2,2),(y,-2,2)),viewer='tachyon')
show(plot3d(sin(x)*cos(y)-sin(y)*cos(x),(x,-2,2),(y,-2,2)),viewer='tachyon')