Question 162560
{{{ graph( 300, 300, -8, 8, -10, 6, 6*sin(0.7854*(x+2))-3 )}}} 
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Maximum is 3, max of sin=1, 6(1)-3=3
Minimum is -9, min of sin=-1, 6(-1)-3=-9
Axis of wave, not sure what that means. 
Do you mean the offset from the y axis (average y) as shown in green? 
That would be (1/2)(Max+Min)=(1/2)(3+(-9))=-3. 
{{{ graph( 300, 300, -8, 8, -10, 6, 6*sin(0.7854*(x+2))-3,-3 )}}}