ACT Math : ACT Math

Study concepts, example questions & explanations for ACT Math

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Example Questions

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

Find the domain of .  Assume  is for all real numbers.

Possible Answers:

Correct answer:

Explanation:

The domain of  does not exist at , for  is an integer.  

The ends of every period approaches to either positive or negative infinity. Notice that for this problem, the entire graph shifts to the right  units. This means that the asymptotes would also shift right by the same distance.

The asymptotes will exist at:

Therefore, the domain of  will exist anywhere EXCEPT:

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

Find the range of: 

Possible Answers:

Correct answer:

Explanation:

The function  is related to .  The range of the tangent function is .

The range of  is unaffected by the amplitude and the y-intercept.  Therefore, the answer is .

Example Question #2951 : Act Math

What is the range of the trigonometric fuction defined by:
?

Possible Answers:

Correct answer:

Explanation:

For tangent and cotangent functions, the range is always all real numbers. 

Example Question #2952 : Act Math

What is the range of the given trigonometric function:

Possible Answers:

Correct answer:

Explanation:

The range of a function is every value that the funciton's results take. For tangent and cotangent, the function spans from  and so the range is:

Example Question #1 : How To Find A Reference Angle

Which of the following is equivalent to cot(θ)sec(θ)sin(θ)

 

Possible Answers:

–sec(θ)

cot(θ)

1

tan(θ)

0

Correct answer:

1

Explanation:

The first thing to do is to breakdown the meaning of each trig function, cot = cos/sin, sec = 1/cos, and sin = sin. Then put these back into the function and simplify if possible, so then (cos (Θ)/sin (Θ))*(1/cos (Θ))*(sin (Θ)) = (cos (Θ)*sin(Θ))/(sin (Θ)*cos(Θ)) = 1, since they all cancel out. 

Example Question #1 : Reference Angles

Using trigonometry identities, simplify sinθcos2θ – sinθ

Possible Answers:

cos2θsinθ

None of these answers are correct

–sin3θ

cos3θ

sin2θcosθ

Correct answer:

–sin3θ

Explanation:

Factor the expression to get sinθ(cos2θ – 1). 

The trig identity cos2θ + sin2θ = 1 can be reworked to becomes cos2θ – 1 = –sinθ resulting in the simplification of –sin3θ.

Example Question #2 : How To Find A Reference Angle

Using trig identities, simplify sinθ + cotθcosθ

Possible Answers:

cscθ

tanθ

cos2θ

secθ

sin2θ

Correct answer:

cscθ

Explanation:

Cotθ can be written as cosθ/sinθ, which results in sinθ + cos2θ/sinθ.

Combining to get a single fraction results in (sin2θ + cos2θ)/sinθ. 

Knowing that sin2θ + cos2θ = 1, we get 1/sinθ, which can be written as cscθ.

Example Question #1 : Reference Angles

Simplify sec4Θ – tan4Θ.

Possible Answers:

secΘ + sinΘ

sinΘ + cosΘ

cosΘ – sinΘ

tan2Θ – sin2Θ

sec2Θ + tan2Θ

Correct answer:

sec2Θ + tan2Θ

Explanation:

Factor using the difference of two squares:  a2 – b2 = (a + b)(a – b)

The identity 1 + tan2Θ = sec2Θ which can be rewritten as 1 = sec2Θ – tan2Θ

So sec4Θ – tan4Θ = (sec2Θ + tan2Θ)(sec2Θ – tan2Θ) = (sec2Θ + tan2Θ)(1) = sec2Θ + tan2Θ

Example Question #2953 : Act Math

Evaluate the expression below.

Possible Answers:

\frac{1 + \sqrt{2}}{2}

\frac{1 + \sqrt{3}}{2}

\frac{2 + \sqrt{2}}{2}

\sqrt{2}

\frac{2 + \sqrt{3}}{2}

Correct answer:

\frac{2 + \sqrt{2}}{2}

Explanation:

At , sine and cosine have the same value.

Cotangent is given by .

Now we can evaluate the expression.

Example Question #3 : How To Find A Reference Angle

What is the reference angle of an angle that measures 3510 in standard  position?

 

 

Possible Answers:

369

351

109

90

Correct answer:

90

Explanation:

3600 – 3510 = 90

 

 

 

 

 

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