Question

state the amplitude, period, and phase shift of the function -0.4 sin (10x+pie/2)

Answer 1

If you have a function

y = a*sin(k(x-c))

then the
amplitude = |a|
period is 2π/|k|
phase shift is c

so, rewriting your function

y = -.4sin(10(x+π/20))

now just read off the amplitude, period, and phase shift.