1.Relevant points before starting Economics for Class XI

Now a days the questions asked by CBSE involves higher order thinking skills so it becomes mendatory to give more importance to application rather having only knowledge.
At this point I would like to mention thatan approach is required which is deliberate and concious and involves some specific skills.
The most confusing part is to deal with data and diagrams.Understanding of contents become quite easy if you are well versed with the nature of data and curves.
The second part of the preparetion is dividing the topics on the basis of memory level ,understanding level and application level.For example any farmula to measure national income should be first viewed on the basis of memory level and then understanding level.In the same manner consumers Equilibrium should be viewed first at understanding level and then at memory level.
Solving of numerical problems involve memory level then application level and then understanding level methodology.

2.Nature of Data-Total and Marginal

Marginal is net addition to total.Suppose you buy one more note book how much more you have to spend.marginal is the diffrence between two consecutive total values.
Total value can be got by cumulative addition of marginal values.
The data related to marginal value may increase ,may decrease may be constant,may be zero or may be negative.
The Data related with total value behave on the basis of marginal value.

#if marginal value is positive total value will always increase.But the rate of increase depends on the nature of marginal.I mean whether the marginal value is rising ,falling or constant.

If marginal rises total will increase at increasing rate.
If marginal falls total will increase at diminishing rate.
If marginal is constant total will increase at constant rate.
if marginal becomes negative total will start fall down.

3.Shapes of Marginal curves.

Marginal Data determines Total Data .In fact Marginal is the slope of Total.We can define marginal as the net change in total if we move one step ahead or backward.
Marginal curve may be rising ,falling ,constant and may be falling below x axis.
Marginal utility curve always diminishes or falls even reach below x axis.
Marginal product curve first rises then falls and even becomes negative.
Marginal cost curve first falls and then rises.
Marginal revenue in perfect competition is constant.
Marginal revenue in non competitive market is always falling and even reach below x axis.

4. Diffrent total curves-:Total Utility,Total variable cost,Total product and Total revenue curves

This shows the Total Utility curve which increases at diminishing rate.
Reason-:marginal utility is diminishing.
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This diagram shows Total variable cost curve .It initially increases at diminishing rate and then increase at increasing rate.
Reasons-:MC initially falls and then rises.
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This diagram shows Total product curve which initially increases at increases rate then increases at diminishing rate and then starts falling down.
Reason-:MP initially rises and then falls.
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This diagram shows Total revenue curve in perfect competition which is increases at constant rate.
Reason -:MR is constant.
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5.Shapes of diffrent curves

This diagram shows the total curve increases at increasing rate.
Note -:It slopes towards 'x' axis

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This diagram shows that the total curve is increases at constant rate.
Note-:It is straight line.

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This diagram shows that total curve is increases at diminishing rate.
Note-:It slopes towards 'y' axis.