All Precalculus Resources
Example Questions
Example Question #1211 : Pre Calculus
Evaluate the logarithm
Given the property
and because
we obtain that
Example Question #1212 : Pre Calculus
Evaluate to four decimal places:
Using a calculator, evaluate
Example Question #1213 : Pre Calculus
Evaluate to 4 decimal places:
To evaluate, use a calculator to find
Example Question #1214 : Pre Calculus
Evaluate the following:
To solve, simply find the matching base and use properties of logs to simplify.
Some properties of logs include the following:
1)
2)
3)
Thus,
Example Question #1214 : Pre Calculus
Evaluate the following:
To solve, remember the following rules for logarithms.
Thus,
Remember, if a base isn't specified, it is 10.
Example Question #1 : Solve Exponential Equations
Solve an equation involving exponents and logarithms.
Solve for .
First, simplify the left side of the equation using the additive rule for exponents.
.
Our equation now becomes:
Equating we set the exponents equal to eachother and solve.
Thus,
Example Question #2 : Exponential Functions
Solve an exponential equation.
Solve for .
First, use the additive property of exponents to simplify the right side of the equation.
.
Thus,
.
Now, take the natural log of both sides
.
Use the multiplicative property of logarithms to expand the left side to get
Now, apply the logarithms to the exponents
.
Rearrange to get the x-terms on one side
.
Finally, divide the 2 on both sides
.
Example Question #3 : Exponential Functions
Solve for .
First, let's begin by simplifying the left hand side.
becomes and becomes . Remember that , and the in that expression can come out to the front, as in .
Now, our expression is
From this, we can cancel out the 2's and an x from both sides.
Thus our answer becomes:
.
Example Question #4 : Solve Exponential Equations
The population of fish in a pond is modeled by the exponential function
, where is the population of fish and is the number of years since January 2010.
Determine the population of fish in January 2010 and January 2015.
2010: fish
2015: fish
2010: fish
2015: fish
2010: fish
2015: fish
2010: fish
2015: fish
2010: fish
2015: fish
In 2010, in our equation because we have had no years past 2010. Plugging that in to the model equation and solving:
, since anything raised to the power of zero becomes . So the population of fish in 2010 is fish.
In 2015, because 5 years have passed since 2010. Plugging that into our equation and solving gives us
So the population of fish in 2015 is fish. This is an example of exponential decay since the function is decreasing.
Example Question #5 : Solve Exponential Equations
Solve for using properties of exponents.
Since , the equation simplifies to .
Since the bases are equal, we can then set the exponents equal to each other.
Solving for x in this simple equation gives the correct answer.