• Support PF! Buy your school textbooks, materials and every day products Here!

Solving absolute values of trigonometry

  • Thread starter Physics53
  • Start date
  • #1
9
0

Homework Statement


math question.PNG


Homework Equations




The Attempt at a Solution


2sin3x=1 OR 2sin3x= -1
sin3x=1/2 sin3x= -1/2
From the unit circle and in accordance with the domain
there are 3 solutions (B)
But the answer is (C)
HOW?
 

Attachments

Answers and Replies

  • #2
Ray Vickson
Science Advisor
Homework Helper
Dearly Missed
10,706
1,728

Homework Statement


View attachment 229661

Homework Equations




The Attempt at a Solution


2sin3x=1 OR 2sin3x= -1
sin3x=1/2 sin3x= -1/2
From the unit circle and in accordance with the domain
there are 3 solutions (B)
But the answer is (C)
HOW?
In your problem, ##\theta = 3x## runs from ##\theta = 0## to ##\theta = 3 \pi.## Look at a plot of ##y = \sin \theta## for ##0 \leq \theta \leq 3 \pi.## How many places are there at which ##\sin \theta = 1/2## or ##\theta = -1/2?##
 

Related Threads on Solving absolute values of trigonometry

  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
4
Views
1K
Replies
2
Views
1K
  • Last Post
Replies
7
Views
1K
  • Last Post
Replies
3
Views
904
  • Last Post
Replies
6
Views
2K
  • Last Post
Replies
9
Views
1K
Replies
3
Views
1K
Top