Trig graphs

[carmine stream]

we know the maximum of the sin function is 1, because the graph goes to y = 2, we can tell this is going to be y = 2 sin(bx) so a = 2, now because x=90 at y = 2sin(bx) we know that b must equal 1 because y = 2sin(90) gives 2 which is what the graph also tells us