A fly is standing on a boulder, which is rolling down a hill. The forward torque the fly exerts on the boulder when it has rolled x xx meters, in newton meters, is given by τ ( x ) = 2 1000 sin ⁡ ( 2 π ( x + 0.2 ) 4 ) τ(x)= 1000 2 sin( 4 2π(x+0.2) )tau, left parenthesis, x, right parenthesis, equals, start fraction, 2, divided by, 1000, end fraction, sine, left parenthesis, start fraction, 2, pi, left parenthesis, x, plus, 0, point, 2, right parenthesis, divided by, 4, end fraction, right parenthesis. What is the midline of this function? Give an exact answer. y =