y=-2sin((2\(\pi\)/7)x)
y = asin(bx+c)+d and the period is given by the equation T = 2\(\pi\)/b
where T is the period of the function. "a" changes the amplitude only (vertical stretch). ""c" is the left/right phase shift. "d" moves the whole graph up or down.
The coefficient of x in (2\(\pi\)/7)x is 2 pi/7 which would also be equal to b.
T = 2\(\pi\)/(2\(\pi\)/7) = 7
