General solutions where f(x) = kepx (exponential types)
General solutions where f(x) = kepx (exponential types)
Principles of Exponential Equations
Defining Exponential Equations
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Exponential equations are mathematical expressions that describe growth or decay phenomena.
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These equations take the form f(x) = kepx, where ‘k’ and ‘p’ are constants, ‘e’ is the base of natural logarithms (approximately equal to 2.71828), and ‘x’ is the variable.
Solution Strategies for Exponential Equations
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When given an equation of the form f(x) = kepx, start solving by substituting given values (if any) into the equation.
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Peel off any added or subtracted terms to the exponential term in stages until the exponential term stands alone on one side of the equation.
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If you are left with an equation kepx = a, where ‘a’ is a constant, take the natural log of both sides: ln(kepx) = ln(a).
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Utilising the properties of logarithms, simplify e^px to yield px = ln(a/k).
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To isolate ‘x’, divide both sides of the equation by ‘p’: x = (ln(a/k))/p.
Example of an Exponential Equation Solution
Problem:
- If we have the function f(x) = 3e2x = 9.
Solution:
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To isolate the exponential term, we divide both sides by 3, leaving e2x = 3.
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Taking the natural logarithm on both sides, we get 2x = ln(3).
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Lastly, we find x by dividing the equation by 2: x = (ln(3))/2.
Applications in Mathematics
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Exponential equations are pivotal in physics, economics, biology, and many more fields.
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Understanding how to solve this type of equation can help simplify problems related to exponential growth or decay, such as population growth, radioactive decay, and compound interest.