howto write an equation of the sine function with amplitude 0.8 and period is pi

Question

this is my homework for my pre cal class and it is due tomorrow

 

i just do not understand how to write an equation using those numbers

Answer 1

f(x)=0.4sin(2x) has an amplitude of 0.8 because sin varies between -1 and 1, f(x) varies between -0.4 and 0.4 the difference being 0.8 which is the height of the sine wave. The period of sine is 2(pi), when x2=x1+(pi) sin(2x2)=sin(2x1) because sin(2x2)=sin(2(x1+(pi))=sin(2x1+2(pi))=sin(2x1).