A decrease in interest rates resulting from an expansionary monetary policy can boost investment spending, shifting the aggregate demand curve to the right.

An expansionary monetary policy that increases the money supply always leads to an increase in interest rates and a leftward shift of the aggregate demand curve.

Monetary policy influences aggregate demand through its effect on interest rates, which in turn affect consumption, investment, and net exports.

Contractionary monetary policy, which raises interest rates, tends to reduce aggregate demand by curbing investment expenditure.