The general form of a sine function is:y=asin(bx+c)where a is the amplitude, b is the coefficient of the angle, and c is the phase shift.To find the period of the function, we have to divide the regular period of a sine function, which is 2π, by the coefficient of the angle.Therefore, the period of the above general sine function would be:

b

2π

.

In this problem, the period is given as T=10. This means:

b

2π

=10

2π=10b

b=

5

π

If we assume there is no phase shift. i.e. c=0 then our sine function would be:

y=0.75sin(

5

π

x)

y(4)=0.75sin(

5

π

(4))

y(4)=0.75sin(

5

4π

)=0.75(0.044)=0.033