Precalculus : Pre-Calculus

Study concepts, example questions & explanations for Precalculus

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Example Questions

Example Question #2 : Inverse Trigonometric Functions

Evaluate:  

Possible Answers:

Correct answer:

Explanation:

To determine the value of , solve each of the terms first.

The inverse cosine has a domain and range restriction.

The domain exists from , and the range from .  The inverse cosine asks for the angle when the x-value of the existing coordinate is .  The only possibility is  since the coordinate can only exist in the first quadrant.

The inverse sine also has a domain and range restriction.

The domain exists from , and the range from .  The inverse sine asks for the angle when the y-value of the existing coordinate is .  The only possibility is  since the coordinate can only exist in the first quadrant.

Therefore:

Example Question #1 : Inverse Trigonometric Functions

Evaluate the following:

Possible Answers:

Correct answer:

Explanation:

For this particular problem we need to recall that the inverse cosine cancels out the cosine therefore,

.

So the expression just becomes 

From here, recall the unit circle for specific angles such as .

Thus,

.

Example Question #2 : Evaluate Expressions That Include The Inverse Tangent, Cosecant, Secant, Or Cotangent Function

Determine the value of  in degrees.

Possible Answers:

Correct answer:

Explanation:

Rewrite and evaluate .

The inverse sine of one-half is  since  is the y-value of the coordinate when the angle is .

To convert from radians to degrees, replace  with 180.

 

Example Question #4 : Evaluate Expressions That Include The Inverse Tangent, Cosecant, Secant, Or Cotangent Function

Evaluate the following expression: 

Possible Answers:

Correct answer:

Explanation:

This one seems complicated, but becomes considerably easier once you implement the fact that the composite  cancels out to 1 and you are left with  which is equal to 1

 

Example Question #851 : Pre Calculus

Evaluate: 

Possible Answers:

Correct answer:

Explanation:

 

Example Question #852 : Pre Calculus

Approximate the following: 

Possible Answers:

Correct answer:

Explanation:

This one is rather simple with knowledge of the unit circle: the value is extremely close to zero, of which  always

 

Example Question #854 : Pre Calculus

Given that   and that  is acute, find the value of  without using a calculator.

Possible Answers:

Correct answer:

Explanation:

Given the value of the opposite and hypotenuse sides from the sine expression (3 and 4 respectively) we can use the Pythagorean Theorem to find the 3rd side (we’ll call it “t”): . From here we can easily deduce the value of  (the adjacent side over the opposite side) 

 

Example Question #3 : Evaluate Expressions That Include The Inverse Tangent, Cosecant, Secant, Or Cotangent Function

Given that  and that  is acute, find the value of  without using a calculator.

Possible Answers:

Correct answer:

Explanation:

Given the value of the opposite and hypotenuse sides from the sine expression (3 and 4 respectively) we can use the Pythagorean Theorem to find the 3rd side (we’ll call it “t”): .

From here we can deduce the value of  (the adjacent side over the opposite side) and so the answer is .

Example Question #5 : Inverse Trigonometric Functions

Evaluate the following expression: 

Possible Answers:

Correct answer:

Explanation:

This one seems complicated but becomes considerably easier once you implement the fact that the composite  cancels out to  and you are left with  which is equal to , and so the answer is .

Example Question #853 : Pre Calculus

Approximate the following:  is closest in value to which of the following?

Possible Answers:

1

0

0.2

2

4

Correct answer:

0

Explanation:

This problem is quite manageable with knowledge of the unit circle: the value is extremely close to zero, of which  always, so the only reasonable estimation of this value is 0.

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