<< Chapter < Page Chapter >> Page >

Find a simplified expression for sin ( tan 1 ( 4 x ) ) for 1 4 x 1 4 .

4 x 16 x 2 + 1

Got questions? Get instant answers now!

Access this online resource for additional instruction and practice with inverse trigonometric functions.

Visit this website for additional practice questions from Learningpod.

Key concepts

  • An inverse function is one that “undoes” another function. The domain of an inverse function is the range of the original function and the range of an inverse function is the domain of the original function.
  • Because the trigonometric functions are not one-to-one on their natural domains, inverse trigonometric functions are defined for restricted domains.
  • For any trigonometric function f ( x ) , if x = f 1 ( y ) , then f ( x ) = y . However, f ( x ) = y only implies x = f 1 ( y ) if x is in the restricted domain of f . See [link] .
  • Special angles are the outputs of inverse trigonometric functions for special input values; for example, π 4 = tan 1 ( 1 ) and π 6 = sin 1 ( 1 2 ) . See [link] .
  • A calculator will return an angle within the restricted domain of the original trigonometric function. See [link] .
  • Inverse functions allow us to find an angle when given two sides of a right triangle. See [link] .
  • In function composition, if the inside function is an inverse trigonometric function, then there are exact expressions; for example, sin ( cos 1 ( x ) ) = 1 x 2 . See [link] .
  • If the inside function is a trigonometric function, then the only possible combinations are sin 1 ( cos x ) = π 2 x if 0 x π and cos 1 ( sin x ) = π 2 x if π 2 x π 2 . See [link] and [link] .
  • When evaluating the composition of a trigonometric function with an inverse trigonometric function, draw a reference triangle to assist in determining the ratio of sides that represents the output of the trigonometric function. See [link] .
  • When evaluating the composition of a trigonometric function with an inverse trigonometric function, you may use trig identities to assist in determining the ratio of sides. See [link] .

Section exercises


Why do the functions f ( x ) = sin 1 x and g ( x ) = cos 1 x have different ranges?

The function y = sin x is one-to-one on [ π 2 , π 2 ] ; thus, this interval is the range of the inverse function of y = sin x , f ( x ) = sin 1 x . The function y = cos x is one-to-one on [ 0 , π ] ; thus, this interval is the range of the inverse function of y = cos x , f ( x ) = cos 1 x .

Got questions? Get instant answers now!

Since the functions y = cos x and y = cos 1 x are inverse functions, why is cos 1 ( cos ( π 6 ) ) not equal to π 6 ?

Got questions? Get instant answers now!

Explain the meaning of π 6 = arcsin ( 0.5 ) .

π 6 is the radian measure of an angle between π 2 and π 2 whose sine is 0.5.

Got questions? Get instant answers now!

Most calculators do not have a key to evaluate sec 1 ( 2 ) . Explain how this can be done using the cosine function or the inverse cosine function.

Got questions? Get instant answers now!

Why must the domain of the sine function, sin x , be restricted to [ π 2 , π 2 ] for the inverse sine function to exist?

In order for any function to have an inverse, the function must be one-to-one and must pass the horizontal line test. The regular sine function is not one-to-one unless its domain is restricted in some way. Mathematicians have agreed to restrict the sine function to the interval [ π 2 , π 2 ] so that it is one-to-one and possesses an inverse.

Got questions? Get instant answers now!

Questions & Answers

How look for the general solution of a trig function
collins Reply
stock therom F=(x2+y2) i-2xy J jaha x=a y=o y=b
Saurabh Reply
root under 3-root under 2 by 5 y square
Himanshu Reply
The sum of the first n terms of a certain series is 2^n-1, Show that , this series is Geometric and Find the formula of the n^th
amani Reply
Aasik Reply
why two x + seven is equal to nineteen.
Kingsley Reply
The numbers cannot be combined with the x
2x + 7 =19
2x +7=19. 2x=19 - 7 2x=12 x=6
because x is 6
what is the best practice that will address the issue on this topic? anyone who can help me. i'm working on my action research.
Melanie Reply
simplify each radical by removing as many factors as possible (a) √75
Jason Reply
how is infinity bidder from undefined?
Karl Reply
what is the value of x in 4x-2+3
Vishal Reply
give the complete question
4x=3-2 4x=1 x=1+4 x=5 5x
hi can you give another equation I'd like to solve it
what is the value of x in 4x-2+3
if 4x-2+3 = 0 then 4x = 2-3 4x = -1 x = -(1÷4) is the answer.
4x-2+3 4x=-3+2 4×=-1 4×/4=-1/4
then x=-1/4
4x-2+3 4x=-3+2 4x=-1 4x÷4=-1÷4 x=-1÷4
A research student is working with a culture of bacteria that doubles in size every twenty minutes. The initial population count was  1350  bacteria. Rounding to five significant digits, write an exponential equation representing this situation. To the nearest whole number, what is the population size after  3  hours?
David Reply
v=lbh calculate the volume if i.l=5cm, b=2cm ,h=3cm
Haidar Reply
Need help with math
can you help me on this topic of Geometry if l help you
( cosec Q _ cot Q ) whole spuare = 1_cosQ / 1+cosQ
Aarav Reply
A guy wire for a suspension bridge runs from the ground diagonally to the top of the closest pylon to make a triangle. We can use the Pythagorean Theorem to find the length of guy wire needed. The square of the distance between the wire on the ground and the pylon on the ground is 90,000 feet. The square of the height of the pylon is 160,000 feet. So, the length of the guy wire can be found by evaluating √(90000+160000). What is the length of the guy wire?
Maxwell Reply
the indicated sum of a sequence is known as
Arku Reply
Practice Key Terms 6

Get the best Algebra and trigonometry course in your pocket!

Source:  OpenStax, Algebra and trigonometry. OpenStax CNX. Nov 14, 2016 Download for free at https://legacy.cnx.org/content/col11758/1.6
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Algebra and trigonometry' conversation and receive update notifications?