The economic expense that must be specified to buy or maintain a service or a product is called **cost**. **Marginal**, for its part, is what is on the margin, is scarce or is secondary.

In the economic sphere, it is called **marginal cost** to the **increase** of the **production cost** what is generated when **increases the quantity produced by one unit**. It should be remembered that the cost of production refers to the money that must be disbursed to produce a service or a good.

Ultimately, the aforementioned definition indicates that marginal cost is the increase in cost recorded when an additional unit of a certain good is produced. In other words, marginal cost reflects the **rate of cost change divided by the change in the level of** **production**.

Suppose a **company** of sportswear produces **100 pants** with a **cost** from **500 dollars**. Yes, when producing **120 pants**, the cost of production rises to **$ 510**, the **marginal cost** it will be of **$ 0.5**:

*Marginal cost = Variation in cost / Variation in productionMarginal cost = $ 10/20 pantsMarginal cost = $ 0.5 per pair of pants*

This means that, for **produce an extra pair of pants**, the **company** in question must **increase your production cost by $ 0.5**. If the marginal cost is **$ 0.5 per pair of pants**, and the company produces **20 more pants**, your production cost will increase by **10 dollars**. On the other hand, if it happens to produce **50 extra pants**, the production cost will increase by **25 dollars**.

This concept belongs to the fields of ** economy** and the

**finance**, and is also known as

*cost*marginal. From a strictly mathematical point of view, it can be said that the marginal cost should be expressed as the

**derivative**of the function of

**Total cost**, taking as a reference the quantity in which the production has been modified, which in the previous example is represented with two dozen extra pants.

It is understood by **derivative**, in the field of mathematics, to the function that serves to measure the speed with which its own value changes, depending on the change that its independent variable goes through. Here two more concepts are added:

***** we say that a magnitude is **function** on the other when its value depends on that of the other (for example, the area of a square is a function of the extension of its sides, since they must be multiplied together to give this result);

***** the **independent variable** of a function is one to which we can assign various values within a predefined set to modify the value of the dependent. In the previous case, we could say that the area is the dependent variable, and the sides are the independent ones.

The **Total cost**, mentioned above, is the result of adding the fixed and variable costs. The fixed are those that in the short term have no relation to the level of production of a company, but are stipulated in advance and are carried out regardless of performance. The variables, on the other hand, do depend on the amount that is used of any variable factor, that is, on the resources and the production capacity.

Returning to marginal cost, it is said that its evolution must be represented by a curve shaped like **parable** concave, that is, it starts decreasing and then increases (like a letter **OR**), something that is justified by the **law of diminishing returns**, which indicates that: if a productive factor is added and the others remain constant, then the marginal increase decreases.

By observing the marginal cost curve, we note that at its minimum point is the amount of goods that the company must produce for the **benefit** be minimal.