Answer:
Economists use the term marginal change to describe small incremental adjustments to an existing plan of action. In simple words, Marginal changes are very small incremental changes which don't affect the larger (macroeconomics) totals except in aggregate.
Explanation:
Definitions by 2 examples
I don't know exactly how to label these. I'll start from the left and go to the right. The formula for all of these questions is Sum = a(1 - r^n)/(1 - r)
Left
The complete series is 1 3 9 27 81 and just adding these as you see them, you get 1 + 3 + 9 + 27 + 81 = 121
Sample calculation
i = 1
3^(1 -1) = 1
i = 4
1 * 3^(4 - 1)=3^3 = 27 Just what the series says you should get.
Sum using formula
Sum = 1(1 - 3^5)/(1 - 3) = 1 * (1 - 243)/(1 - 3) = - 242/-2 = 121
Second from the left
Series: 3 6 12 24 48
Sum by hand = 93
Sample Calculation
i = 1
3*2^(1 - 1) = 1
i1 = 3
3 * 2^(3 - 1) = 3 * 2^2 = 3 * 4 = 12 which is what you should get.
Sum using formula
Sum = 3 (1 - 2^(5 - 1) / (1 - 2)
Sum = 3 (1 - 32) / - 1
Sum = 3(-31) / (- 1) = 93
Second from the right.
Series: 2 6 18 54
Sample Calculation
i = 1
t1 = 2* 3^(1 - 1) = 2*3^0 = 2*1 = 2
i = 4
t4 = 2 * 3^(4- 1)
t4 = 2 * 3^3
t4 = 2 * 27
t4 = 54 just as it should
Sum with formula
Sum = 2( 1 - 3^4) / ( 1 - 3)
Sum = 2(1 - 81)/ -2
Sum = 2( - 80) / - 2
Sum = 80
Entry on the right
Series: 1 2 4 8 16 32 64
Sum by hand: 1 + 2 + 4 + 8 + 16 + 32 + 64 = 127
Sample Calculation:
i = 1
2^(1 - 1) = 2^0
2 to the zero = 1
i = 6
t6 = 1( 2^6)
t6 = 1 * 2^6 = 64
Sum using the formula: 1*(1 - 2^7)/(1 - 2) = (1 - 128)/(-1 = 127
Order: Answer
Right comes first
Left
Second from the left
Second from the right.
