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Evaluating functions

Given the function h ( p ) = p 2 + 2 p , evaluate h ( 4 ) .

To evaluate h ( 4 ) , we substitute the value 4 for the input variable p in the given function.

h ( p ) = p 2 + 2 p h ( 4 ) = ( 4 ) 2 + 2 ( 4 ) = 16 + 8 = 24

Therefore, for an input of 4, we have an output of 24.

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Given the function g ( m ) = m 4 , evaluate g ( 5 ) .

g ( 5 ) = 1

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Solving functions

Given the function h ( p ) = p 2 + 2 p , solve for h ( p ) = 3.

h ( p ) = 3 p 2 + 2 p = 3 Substitute the original function  h ( p ) = p 2 + 2 p . p 2 + 2 p 3 = 0 Subtract 3 from each side . ( p + 3 )( p 1 ) = 0 Factor .

If ( p + 3 ) ( p 1 ) = 0 , either ( p + 3 ) = 0 or ( p 1 ) = 0 (or both of them equal 0). We will set each factor equal to 0 and solve for p in each case.

( p + 3 ) = 0 , p = 3 ( p 1 ) = 0 , p = 1

This gives us two solutions. The output h ( p ) = 3 when the input is either p = 1 or p = 3. We can also verify by graphing as in [link] . The graph verifies that h ( 1 ) = h ( 3 ) = 3 and h ( 4 ) = 24.

Graph of a parabola with labeled points (-3, 3), (1, 3), and (4, 24).
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Given the function g ( m ) = m 4 , solve g ( m ) = 2.

m = 8

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Evaluating functions expressed in formulas

Some functions are defined by mathematical rules or procedures expressed in equation    form. If it is possible to express the function output with a formula    involving the input quantity, then we can define a function in algebraic form. For example, the equation 2 n + 6 p = 12 expresses a functional relationship between n and p . We can rewrite it to decide if p is a function of n .

Given a function in equation form, write its algebraic formula.

  1. Solve the equation to isolate the output variable on one side of the equal sign, with the other side as an expression that involves only the input variable.
  2. Use all the usual algebraic methods for solving equations, such as adding or subtracting the same quantity to or from both sides, or multiplying or dividing both sides of the equation by the same quantity.

Finding an equation of a function

Express the relationship 2 n + 6 p = 12 as a function p = f ( n ) , if possible.

To express the relationship in this form, we need to be able to write the relationship where p is a function of n , which means writing it as p = [ expression involving n ] .

2 n + 6 p = 12 6 p = 12 2 n Subtract  2 n  from both sides . p = 12 2 n 6 Divide both sides by 6 and simplify . p = 12 6 2 n 6 p = 2 1 3 n

Therefore, p as a function of n is written as

p = f ( n ) = 2 1 3 n
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Expressing the equation of a circle as a function

Does the equation x 2 + y 2 = 1 represent a function with x as input and y as output? If so, express the relationship as a function y = f ( x ) .

First we subtract x 2 from both sides.

y 2 = 1 x 2

We now try to solve for y in this equation.

y = ± 1 x 2 = + 1 x 2  and  1 x 2

We get two outputs corresponding to the same input, so this relationship cannot be represented as a single function y = f ( x ) . If we graph both functions on a graphing calculator, we will get the upper and lower semicircles.

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If x 8 y 3 = 0 , express y as a function of x .

y = f ( x ) = x 3 2

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Are there relationships expressed by an equation that do represent a function but that still cannot be represented by an algebraic formula?

Yes, this can happen. For example, given the equation x = y + 2 y , if we want to express y as a function of x , there is no simple algebraic formula involving only x that equals y . However, each x does determine a unique value for y , and there are mathematical procedures by which y can be found to any desired accuracy. In this case, we say that the equation gives an implicit (implied) rule for y as a function of x , even though the formula cannot be written explicitly.

Questions & Answers

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In economics, a perfect market refers to a theoretical construct where all participants have perfect information, goods are homogenous, there are no barriers to entry or exit, and prices are determined solely by supply and demand. It's an idealized model used for analysis,
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When MP₁ becomes negative, TP start to decline. Extuples Suppose that the short-run production function of certain cut-flower firm is given by: Q=4KL-0.6K2 - 0.112 • Where is quantity of cut flower produced, I is labour input and K is fixed capital input (K-5). Determine the average product of lab
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Extuples Suppose that the short-run production function of certain cut-flower firm is given by: Q=4KL-0.6K2 - 0.112 • Where is quantity of cut flower produced, I is labour input and K is fixed capital input (K-5). Determine the average product of labour (APL) and marginal product of labour (MPL)
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Quantity demanded refers to the specific amount of a good or service that consumers are willing and able to purchase at a give price and within a specific time period. Demand, on the other hand, is a broader concept that encompasses the entire relationship between price and quantity demanded
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Economic growth as an increase in the production and consumption of goods and services within an economy.but Economic development as a broader concept that encompasses not only economic growth but also social & human well being.
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it is a curve that we get after connecting the pareto optimal combinations of two consumers after their mutually beneficial trade offs
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In economics, the contract curve refers to the set of points in an Edgeworth box diagram where both parties involved in a trade cannot be made better off without making one of them worse off. It represents the Pareto efficient allocations of goods between two individuals or entities, where neither p
Cornelius
In economics, the contract curve refers to the set of points in an Edgeworth box diagram where both parties involved in a trade cannot be made better off without making one of them worse off. It represents the Pareto efficient allocations of goods between two individuals or entities,
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Suppose a consumer consuming two commodities X and Y has The following utility function u=X0.4 Y0.6. If the price of the X and Y are 2 and 3 respectively and income Constraint is birr 50. A,Calculate quantities of x and y which maximize utility. B,Calculate value of Lagrange multiplier. C,Calculate quantities of X and Y consumed with a given price. D,alculate optimum level of output .
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Answer
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the market for lemon has 10 potential consumers, each having an individual demand curve p=101-10Qi, where p is price in dollar's per cup and Qi is the number of cups demanded per week by the i th consumer.Find the market demand curve using algebra. Draw an individual demand curve and the market dema
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suppose the production function is given by ( L, K)=L¼K¾.assuming capital is fixed find APL and MPL. consider the following short run production function:Q=6L²-0.4L³ a) find the value of L that maximizes output b)find the value of L that maximizes marginal product
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What is the difference between perfect competition and monopolistic competition?
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Source:  OpenStax, College algebra. OpenStax CNX. Feb 06, 2015 Download for free at https://legacy.cnx.org/content/col11759/1.3
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