y=-2sin((2[tex] \pi [/tex]/7)x)
y = asin(bx+c)+d and the period is given by the equation T = 2[tex] \pi [/tex]/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[tex] \pi [/tex]/7)x is 2 pi/7 which would also be equal to b.
T = 2[tex] \pi [/tex]/(2[tex] \pi [/tex]/7) = 7
