ACT Math : ACT Math

Study concepts, example questions & explanations for ACT Math

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Example Questions

Example Question #22 : Trigonometry

What is the tangent of the angle formed between the origin and the point  if that angle is formed with one side of the angle beginning on the -axis and then rotating counter-clockwise to ? Round to the nearest hundredth.

 

Possible Answers:

Correct answer:

Explanation:

Recall that when you calculate a trigonometric function for an obtuse angle like this, you always use the -axis as your reference point for your angle. (Hence, it is called the "reference angle.")  

Now, it is easiest to think of this like you are drawing a little triangle in the second quadrant of the Cartesian plane. It would look like: 

Tan174

So, the tangent of an angle is:

  or, for your data, .

This is . Rounding, this is . However, since  is in the second quadrant, your value must be negative. (The tangent function is negative in that quadrant.) Therefore, the answer is .

Example Question #1 : How To Find Negative Tangent

What is the tangent of the angle formed between the origin and the point  if that angle is formed with one side of the angle beginning on the -axis and then rotating counter-clockwise to ? Round to the nearest hundredth.

Possible Answers:

Correct answer:

Explanation:

Recall that when you calculate a trigonometric function for an obtuse angle like this, you always use the -axis as your reference point for your angle. (Hence, it is called the "reference angle.")  

Now, it is easiest to think of this like you are drawing a little triangle in the fourth quadrant of the Cartesian plane. It would look like:

 Tan43

 

So, the tangent of an angle is:

  or, for your data,  or . However, since  is in the fourth quadrant, your value must be negative. (The tangent function is negative in that quadrant.) This makes the correct answer .

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

Which of the following equations represents a tangent function with a period that is  radians?

Possible Answers:

Correct answer:

Explanation:

The standard period of a tangent function is  radians. In other words, it completes its entire cycle of values in that many radians. To alter the period of the function, you need to alter the value of the parameter of the trigonometric function. You multiply the parameter by the number of periods that would complete in  radians. With a period of , you are quadrupling your method. Therefore, you will have a function of the form:

Since  and  do not alter the period, these can be anything.

Therefore, among your options,  is correct.

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

Which of the following represents a tangent function that has a period half that of one with a period of ?

Possible Answers:

Correct answer:

Explanation:

The standard period of a tangent function is  radians. In other words, it completes its entire cycle of values in that many radians. To alter the period of the function, you need to alter the value of the parameter of the trigonometric function. You multiply the parameter by the number of periods that would complete in  radians. With a period of , you are multiplying your parameter by . Now, half of this would be a period of . Thus, you will have a function of the form:

Since  and  do not alter the period, these can be anything.

Therefore, among your options,  is correct.

Example Question #2 : How To Find The Period Of The Tangent

What is the period of the following tangent function?

Possible Answers:

Correct answer:

Explanation:

The period of the tangent function defined in its standard form  has a period of . When you multiply the argument of the trigonometric function by a constant, you shorten its period of repetition. (Think of it like this: You pass through more iterations for each value  that you use.) If you have , this has one fifth of the period of the standard tangent function.  In the equation given, none of the other details matter regarding the period. They alter other aspects of the equation (its "width," its location, etc.). The period is altered only by the parameter. Thus, the period of this function is  of , or .

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

What is the period of the following trigonometric equation:

Possible Answers:

Correct answer:

Explanation:

For tangent and cotangent the period is given by the formula:

 where  comes from .

Thus we see from our equation  and so
.

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

What is the period of the trigonometric function given by:
?

Possible Answers:

Correct answer:

Explanation:

To find the period of a tangent funciton use the following formula:

 where  comes from .

thus we get that  so 

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

What is the period of the following trigonometric function:

Possible Answers:

Correct answer:

Explanation:

To find the period of a tangent or cotangent function use the following formula:

 

from the general tirogonometric formula: 

Since we have,

 

we have

.

Thus we get that 

Example Question #31 : Trigonometry

What is domain of the function  from the interval ?

Possible Answers:

Correct answer:

Explanation:

Rewrite the tangent function in terms of cosine and sine.

Since the denominator cannot be zero, evaluate all values of theta where  on the interval .

These values of theta are asymptotes and will not exist on the tangent curve. They will not be included in the domain and parentheses will be used in the interval notation.

The correct solution is .

Example Question #2 : How To Find The Domain Of The Tangent

Where does the domain NOT exist for ?

Possible Answers:

Correct answer:

Explanation:

The domain for the parent function of tangent does not exist for:

The amplitude and the vertical shift will not affect the domain or the period of the graph.

The tells us that the graph will shift right  units.

Therefore, the asymptotes will be located at:

The locations of the asymptotes are:

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