ACT Math : Trigonometry

Study concepts, example questions & explanations for ACT Math

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Example Questions

Example Question #51 : Trigonometry

What is the reference angle for ?

Possible Answers:

Correct answer:

Explanation:

A reference angle is the smallest possible angle between a given angle measurement and the x-axis.

In this case, our angle  lies in Quadrant III, so the angle is found by the formula .

  

Thus, the reference angle for  is .

Example Question #51 : Trigonometry

What is the reference angle for ?

Possible Answers:

Correct answer:

Explanation:

A reference angle is the smallest possible angle between a given angle measurement and the x-axis.

In this case, our angle  lies in Quadrant II, so we can find our reference angle using the formula

.

  

Thus, the reference angle for  is .

Example Question #1 : How To Find The Period Of The Sine

What is the period of 2sin(4Θ)?

Possible Answers:

None of the answers are correct

Correct answer:

Explanation:

 The period of sinΘ is 2Π, so we set the new angle equal to the base period of 2Π and solve for Θ.

So 4Θ = 2Π and Θ = Π/2.

Example Question #1 : How To Find The Period Of The Sine

A function with period P will repeat on intervals of length P, and these intervals are referred to as periods.

 

Find the period of 

.

Possible Answers:

Correct answer:

Explanation:

For the function

the period is equal to

in this case

which reduces to .

Example Question #1 : Sine

A function with period P will repeat on intervals of length P, and these intervals are referred to as periods.

Find the period of the function

.

Possible Answers:

Correct answer:

Explanation:

For the function

the period is equal to

in this case

which reduces to .

Example Question #3 : How To Find The Period Of The Sine

What is the period of the function ?

Possible Answers:

Correct answer:

Explanation:

To find the period of Sine and Cosine functions you use the formula:
 where  comes from . Looking at our formula you see b is 4 so 

Example Question #52 : Trigonometry

What is the period of the given trigonometric function:

. Leave your answer in terms of , simplify all fractions.

Possible Answers:

Correct answer:

Explanation:

To find the period of a sine, cosine, cosecant, or secant funciton use the formula:

 where  comes from the general formula: . We see that for our equation  and so the period is  when you reduce the fraction.

Example Question #1 : Sine

Find the period of the following formula:

Possible Answers:

Correct answer:

Explanation:

To find period, simply remember the following formula:

where B is the coefficient in front of x. Thus,

Example Question #1 : How To Find The Domain Of The Sine

Find the domain of the function: 

Possible Answers:

Correct answer:

Explanation:

The function  is related to the parent function , which has a domain of .

The value of theta for  has no restriction and is valid for all real numbers.  

The answer is .

 

Example Question #2 : Sine

What is the domain of the given trigonometric function:

Possible Answers:

Correct answer:

Explanation:

For both Sine and Cosine, since there are no asymptotes like Tangent and Cotangent functions, the function can take in any value for . Thus the domain is:

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