, .. . :
1) : C = C (Yd), , .. ,
2) , , , , , . , : Yd = + S, , . , .
:
S = Yd C = Yd (C+ mpc Yd) = - C + (1 mpc) Yd = - C + mps Yd
( ) , , .
3) , /Yd , S/Yd . (.. ) (average propensity to consume apc), (.. ) (average propensity to save aps): apc = C/Yd 0< apc < 1
aps = S/Yd 0< aps < 1
1:
apc + aps = C/Yd + S/Yd = (C + S)/Yd = Yd/Yd = 1
, : mpc LR = apc, ( ) (apc = const). , mpc mpc , apc, . : . , (mpc LR > mpc SR). : = mpc LR (Yd) = apc (Yd)
22. , , .
(marginal propensity to consume mpc) , , () () : mpc = ∆/∆Y , 0< mpc<1
(marginal propensity to save mps) , , () () : mps = ∆S/∆Y 0< mps<1
1: mpc + mps = ∆/∆Y + ∆S/∆Y= (∆ + ∆S)/ ∆Y= ∆Y/∆Y= 1
1)
2) ,
/Yd , S/Yd . (.. ) (average propensity to consume apc), (.. ) (average propensity to save aps): apc = C/Yd 0< apc < 1 aps = S/Yd 0< aps < 1
1: apc + aps = C/Yd + S/Yd = (C + S)/Yd = Yd/Yd = 1