If DAD is upward-sloping and steeper than DAS, then the economy is unstable:output will not return to its natural level, and inflation will spiral upward (for positive demand shocks) or downward (for negative ones).
If DAD is upward-sloping and steeper than DAS, then the economy is unstable:output will not return to its natural level, and inflation will spiral upward (for positive demand shocks) or downward (for negative ones).