Trigonometry Examples

Graph 8sin(2/9x+2/3)
Step 1
Use the form to find the variables used to find the amplitude, period, phase shift, and vertical shift.
Step 2
Find the amplitude .
Amplitude:
Step 3
Find the period of .
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Step 3.1
The period of the function can be calculated using .
Step 3.2
Replace with in the formula for period.
Step 3.3
is approximately which is positive so remove the absolute value
Step 3.4
Multiply the numerator by the reciprocal of the denominator.
Step 3.5
Cancel the common factor of .
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Step 3.5.1
Factor out of .
Step 3.5.2
Cancel the common factor.
Step 3.5.3
Rewrite the expression.
Step 3.6
Move to the left of .
Step 4
Find the phase shift using the formula .
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Step 4.1
The phase shift of the function can be calculated from .
Phase Shift:
Step 4.2
Replace the values of and in the equation for phase shift.
Phase Shift:
Step 4.3
Multiply the numerator by the reciprocal of the denominator.
Phase Shift:
Step 4.4
Cancel the common factor of .
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Step 4.4.1
Move the leading negative in into the numerator.
Phase Shift:
Step 4.4.2
Factor out of .
Phase Shift:
Step 4.4.3
Cancel the common factor.
Phase Shift:
Step 4.4.4
Rewrite the expression.
Phase Shift:
Phase Shift:
Step 4.5
Cancel the common factor of .
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Step 4.5.1
Factor out of .
Phase Shift:
Step 4.5.2
Cancel the common factor.
Phase Shift:
Step 4.5.3
Rewrite the expression.
Phase Shift:
Phase Shift:
Step 4.6
Multiply by .
Phase Shift:
Phase Shift:
Step 5
List the properties of the trigonometric function.
Amplitude:
Period:
Phase Shift: ( to the left)
Vertical Shift: None
Step 6
Select a few points to graph.
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Step 6.1
Find the point at .
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Step 6.1.1
Replace the variable with in the expression.
Step 6.1.2
Simplify the result.
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Step 6.1.2.1
Multiply by .
Step 6.1.2.2
Simplify each term.
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Step 6.1.2.2.1
Cancel the common factor of and .
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Step 6.1.2.2.1.1
Factor out of .
Step 6.1.2.2.1.2
Cancel the common factors.
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Step 6.1.2.2.1.2.1
Factor out of .
Step 6.1.2.2.1.2.2
Cancel the common factor.
Step 6.1.2.2.1.2.3
Rewrite the expression.
Step 6.1.2.2.2
Move the negative in front of the fraction.
Step 6.1.2.3
Combine fractions.
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Step 6.1.2.3.1
Combine the numerators over the common denominator.
Step 6.1.2.3.2
Simplify the expression.
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Step 6.1.2.3.2.1
Add and .
Step 6.1.2.3.2.2
Divide by .
Step 6.1.2.4
The exact value of is .
Step 6.1.2.5
Multiply by .
Step 6.1.2.6
The final answer is .
Step 6.2
Find the point at .
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Step 6.2.1
Replace the variable with in the expression.
Step 6.2.2
Simplify the result.
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Step 6.2.2.1
Simplify each term.
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Step 6.2.2.1.1
Cancel the common factor of and .
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Step 6.2.2.1.1.1
Factor out of .
Step 6.2.2.1.1.2
Cancel the common factors.
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Step 6.2.2.1.1.2.1
Factor out of .
Step 6.2.2.1.1.2.2
Cancel the common factor.
Step 6.2.2.1.1.2.3
Rewrite the expression.
Step 6.2.2.1.2
Simplify the numerator.
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Step 6.2.2.1.2.1
To write as a fraction with a common denominator, multiply by .
Step 6.2.2.1.2.2
Combine and .
Step 6.2.2.1.2.3
Combine the numerators over the common denominator.
Step 6.2.2.1.2.4
Multiply by .
Step 6.2.2.1.3
Combine and .
Step 6.2.2.1.4
Reduce the expression by cancelling the common factors.
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Step 6.2.2.1.4.1
Factor out of .
Step 6.2.2.1.4.2
Cancel the common factor.
Step 6.2.2.1.4.3
Rewrite the expression.
Step 6.2.2.1.5
Multiply the numerator by the reciprocal of the denominator.
Step 6.2.2.1.6
Multiply .
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Step 6.2.2.1.6.1
Multiply by .
Step 6.2.2.1.6.2
Multiply by .
Step 6.2.2.2
To write as a fraction with a common denominator, multiply by .
Step 6.2.2.3
Write each expression with a common denominator of , by multiplying each by an appropriate factor of .
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Step 6.2.2.3.1
Multiply by .
Step 6.2.2.3.2
Multiply by .
Step 6.2.2.4
Combine the numerators over the common denominator.
Step 6.2.2.5
Simplify the numerator.
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Step 6.2.2.5.1
Multiply by .
Step 6.2.2.5.2
Add and .
Step 6.2.2.5.3
Add and .
Step 6.2.2.6
Cancel the common factor of and .
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Step 6.2.2.6.1
Factor out of .
Step 6.2.2.6.2
Cancel the common factors.
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Step 6.2.2.6.2.1
Factor out of .
Step 6.2.2.6.2.2
Cancel the common factor.
Step 6.2.2.6.2.3
Rewrite the expression.
Step 6.2.2.7
The exact value of is .
Step 6.2.2.8
Multiply by .
Step 6.2.2.9
The final answer is .
Step 6.3
Find the point at .
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Step 6.3.1
Replace the variable with in the expression.
Step 6.3.2
Simplify the result.
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Step 6.3.2.1
Simplify each term.
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Step 6.3.2.1.1
Cancel the common factor of and .
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Step 6.3.2.1.1.1
Factor out of .
Step 6.3.2.1.1.2
Cancel the common factors.
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Step 6.3.2.1.1.2.1
Factor out of .
Step 6.3.2.1.1.2.2
Cancel the common factor.
Step 6.3.2.1.1.2.3
Rewrite the expression.
Step 6.3.2.1.2
Simplify the numerator.
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Step 6.3.2.1.2.1
To write as a fraction with a common denominator, multiply by .
Step 6.3.2.1.2.2
Combine and .
Step 6.3.2.1.2.3
Combine the numerators over the common denominator.
Step 6.3.2.1.2.4
Multiply by .
Step 6.3.2.1.3
Combine and .
Step 6.3.2.1.4
Reduce the expression by cancelling the common factors.
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Step 6.3.2.1.4.1
Reduce the expression by cancelling the common factors.
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Step 6.3.2.1.4.1.1
Cancel the common factor.
Step 6.3.2.1.4.1.2
Rewrite the expression.
Step 6.3.2.1.4.2
Divide by .
Step 6.3.2.2
Simplify terms.
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Step 6.3.2.2.1
Combine the numerators over the common denominator.
Step 6.3.2.2.2
Simplify by adding numbers.
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Step 6.3.2.2.2.1
Add and .
Step 6.3.2.2.2.2
Add and .
Step 6.3.2.2.3
Cancel the common factor of .
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Step 6.3.2.2.3.1
Cancel the common factor.
Step 6.3.2.2.3.2
Divide by .
Step 6.3.2.3
Apply the reference angle by finding the angle with equivalent trig values in the first quadrant.
Step 6.3.2.4
The exact value of is .
Step 6.3.2.5
Multiply by .
Step 6.3.2.6
The final answer is .
Step 6.4
Find the point at .
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Step 6.4.1
Replace the variable with in the expression.
Step 6.4.2
Simplify the result.
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Step 6.4.2.1
Simplify each term.
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Step 6.4.2.1.1
Cancel the common factor of and .
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Step 6.4.2.1.1.1
Factor out of .
Step 6.4.2.1.1.2
Cancel the common factors.
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Step 6.4.2.1.1.2.1
Factor out of .
Step 6.4.2.1.1.2.2
Cancel the common factor.
Step 6.4.2.1.1.2.3
Rewrite the expression.
Step 6.4.2.1.2
Simplify the numerator.
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Step 6.4.2.1.2.1
To write as a fraction with a common denominator, multiply by .
Step 6.4.2.1.2.2
Combine and .
Step 6.4.2.1.2.3
Combine the numerators over the common denominator.
Step 6.4.2.1.2.4
Multiply by .
Step 6.4.2.1.3
Combine and .
Step 6.4.2.1.4
Reduce the expression by cancelling the common factors.
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Step 6.4.2.1.4.1
Factor out of .
Step 6.4.2.1.4.2
Cancel the common factor.
Step 6.4.2.1.4.3
Rewrite the expression.
Step 6.4.2.1.5
Multiply the numerator by the reciprocal of the denominator.
Step 6.4.2.1.6
Multiply .
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Step 6.4.2.1.6.1
Multiply by .
Step 6.4.2.1.6.2
Multiply by .
Step 6.4.2.2
To write as a fraction with a common denominator, multiply by .
Step 6.4.2.3
Write each expression with a common denominator of , by multiplying each by an appropriate factor of .
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Step 6.4.2.3.1
Multiply by .
Step 6.4.2.3.2
Multiply by .
Step 6.4.2.4
Combine the numerators over the common denominator.
Step 6.4.2.5
Simplify the numerator.
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Step 6.4.2.5.1
Multiply by .
Step 6.4.2.5.2
Add and .
Step 6.4.2.5.3
Add and .
Step 6.4.2.6
Cancel the common factor of and .
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Step 6.4.2.6.1
Factor out of .
Step 6.4.2.6.2
Cancel the common factors.
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Step 6.4.2.6.2.1
Factor out of .
Step 6.4.2.6.2.2
Cancel the common factor.
Step 6.4.2.6.2.3
Rewrite the expression.
Step 6.4.2.7
Apply the reference angle by finding the angle with equivalent trig values in the first quadrant. Make the expression negative because sine is negative in the fourth quadrant.
Step 6.4.2.8
The exact value of is .
Step 6.4.2.9
Multiply .
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Step 6.4.2.9.1
Multiply by .
Step 6.4.2.9.2
Multiply by .
Step 6.4.2.10
The final answer is .
Step 6.5
Find the point at .
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Step 6.5.1
Replace the variable with in the expression.
Step 6.5.2
Simplify the result.
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Step 6.5.2.1
Simplify terms.
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Step 6.5.2.1.1
Cancel the common factor of and .
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Step 6.5.2.1.1.1
Factor out of .
Step 6.5.2.1.1.2
Cancel the common factors.
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Step 6.5.2.1.1.2.1
Factor out of .
Step 6.5.2.1.1.2.2
Cancel the common factor.
Step 6.5.2.1.1.2.3
Rewrite the expression.
Step 6.5.2.1.2
Combine the numerators over the common denominator.
Step 6.5.2.2
Simplify each term.
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Step 6.5.2.2.1
Apply the distributive property.
Step 6.5.2.2.2
Multiply by .
Step 6.5.2.2.3
Multiply by .
Step 6.5.2.3
Reduce the expression by cancelling the common factors.
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Step 6.5.2.3.1
Add and .
Step 6.5.2.3.2
Add and .
Step 6.5.2.3.3
Cancel the common factor of and .
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Step 6.5.2.3.3.1
Factor out of .
Step 6.5.2.3.3.2
Cancel the common factors.
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Step 6.5.2.3.3.2.1
Factor out of .
Step 6.5.2.3.3.2.2
Cancel the common factor.
Step 6.5.2.3.3.2.3
Rewrite the expression.
Step 6.5.2.3.3.2.4
Divide by .
Step 6.5.2.4
Subtract full rotations of until the angle is greater than or equal to and less than .
Step 6.5.2.5
The exact value of is .
Step 6.5.2.6
Multiply by .
Step 6.5.2.7
The final answer is .
Step 6.6
List the points in a table.
Step 7
The trig function can be graphed using the amplitude, period, phase shift, vertical shift, and the points.
Amplitude:
Period:
Phase Shift: ( to the left)
Vertical Shift: None
Step 8