/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 15 Determine the constant of variat... [FREE SOLUTION] | 91Ó°ÊÓ

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Determine the constant of variation for each stated condition. \(y\) varies directly as \(x^{2},\) and \(y=45\) when \(x=3\)

Short Answer

Expert verified
The constant `k` of variation is 5.

Step by step solution

01

Write down the direct variation formula

The direct variation formula when the variation is happening with reference to a square is given as \(y=kx^2\), where \(k\) is the constant of variation that we need to find.
02

Substitute given values of x and y into the formula

From the problem, we have \(y = 45\) when \(x = 3\). Substituting these values into the equation from step 1 results in: \(45 = k(3^2)\).
03

Solve the Equation for k

To solve for \(k\), divide both sides of the equation by \(3^2 = 9\): \( \frac{45}{9} = k\), which simplifies to: \(k = 5\).
04

Verification

To verify our answer, we can substitute \(k = 5\) into the original variation equation and check if it holds true for \(y = 45\) when \(x = 3\). Doing so, we get: \(y = 5*(3^2)\) which simplifies to \(y = 45\).

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Understanding the Constant of Variation
In mathematics, the constant of variation, denoted as "\(k\)", plays a vital role in direct variation equations. Direct variation represents a relationship where one variable changes consistently with respect to another variable, often indicated as \(y = kx^n\) for various powers of \(x\).
  • **Direct Relationship:** This means that if one variable increases or decreases, the other does so too, following a proportional pattern.
  • **Constant \(k\):** It's a fixed number that indicates how much \(y\) will change when \(x\) changes by a certain factor.
In the exercise, \(k\) helps us understand how \(y\) is directly proportional to the square of \(x\). Thus, the determination of \(k\) provides the precise mathematical expression of this direct relationship. Once you grasp how to find \(k\), the rest of the problem becomes much clearer.
Algebraic Equations in Direct Variation
An algebraic equation is an equation involving variables and constants, often presented with operators like addition, subtraction, multiplication, or division. In direct variation cases like our exercise's formula \(y = kx^2\), this equation helps establish that relationship.
  • **Structure:** Typically follows the form \(y = kx^n\).
  • **Variables & Constants:** Here, \(y\) and \(x\) are variables, while \(k\) is a constant.
Understanding algebraic equations allows students to represent complex relationships with simplified expressions. In direct variation, the entire equation itself means that the change in \(y\) directly depends on \(x\)'s square when \(k\) is known. By substituting given numbers into the equation, we can solve real-world problems or theoretical exercises.
Step-by-Step Guide to Solving Equations for Direct Variation
Solving equations is a foundational mathematical technique used to isolate a variable and determine its value. Here's how you can solve an equation concerning the direct variation to find the constant of variation \(k\):
  • **Identify the Formula:** Begin with the direct variation form relevant to your problem, such as \(y = kx^2\).
  • **Substitute Known Values:** Next, plug in the given values of \(x\) and \(y\) into the formula.
  • **Perform Arithmetic Operations:** Simplify the resulting equation by performing arithmetic operations to isolate \(k\). For example, dividing both sides by \(x^n\).
  • **Verification:** Check your solution by substituting \(k\) back into the original equation to ensure consistency with given values.
Following these steps in order ensures clarity and correctness in solving equations, making the process less intimidating and more accessible. Practice with various problems to strengthen your equation-solving skills.

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Most popular questions from this chapter

Explain the relationship between the degree of a polynomial function and the number of turning points on its graph.

Use the four-step procedure for solving variation problems given on page 356 to solve. The electrical resistance of a wire varies directly as its length and inversely as the square of its diameter. A wire of 720 feet with \(\frac{1}{4}\)-inch diameter has a resistance of \(1 \frac{1}{2}\) ohms. Find the resistance for 960 feet of the same kind of wire if its diameter is doubled.

The function \(f(x)=-0.00002 x^{3}+0.008 x^{2}-0.3 x\) \(+6.95\) models the number of annual physician visits, \(f(x),\) by a person of age \(x\) a. Graph the function for meaningful values of \(x\) and discuss what the graph reveals in terms of the variables described by the model. b. Use the zero or root feature of your graphing utility to find the age, to the nearest year, for the group that averages 13.43 annual physician visits. c. Verify part (b) using the graph of \(f\).

Use the four-step procedure for solving variation problems given on page 356 to solve. The intensity of illumination on a surface varies inversely as the square of the distance of the light source from the surface. The illumination from a source is 25 foot-candles at a distance of 4 feet. What is the illumination when the distance is 6 feet?

Use a graphing utility to obtain a complete graph for each polynomial function in Exercises \(58-61 .\) Then determine the number of real zeros and the number of nonreal complex zeros for each function. $$ f(x)=3 x^{5}-2 x^{4}+6 x^{3}-4 x^{2}-24 x+16 $$

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