[tex]\qquad\qquad\huge\underline{{\sf Answer}}♨[/tex]
Here we go ~
The required equation is :
[tex] \qquad \sf \dashrightarrow\: y = asin(bx) +k [/tex]
Now, let's find the required values :
period (p) = 4
[distance between any successive Crest or trough]
a = - 3 (flipped)
b = 2π/p = 2π/4 = π/2
k = 1
Distance of starting position from origin = k
Now, plug in the values ~
[tex] \qquad\dashrightarrow \sf\: y = -3sin(\frac{\pi}{2}x)+1 [/tex]
