menu
Qammunity.org
Login
Register
My account
Edit my Profile
Private messages
My favorites
Find sin x/2, cos x/2, and tan x/2, if cos x = -12/13, 180 degrees is less than x which is less than 270 degrees
Ask a Question
Questions
Unanswered
Tags
Ask a Question
Find sin x/2, cos x/2, and tan x/2, if cos x = -12/13, 180 degrees is less than x which is less than 270 degrees
asked
Nov 9, 2017
52.3k
views
4
votes
Find sin x/2, cos x/2, and tan x/2, if cos x = -12/13, 180 degrees is less than x which is less than 270 degrees
Mathematics
high-school
Dario Digregorio
asked
by
Dario Digregorio
8.3k
points
answer
comment
share this
share
0 Comments
Please
log in
or
register
to add a comment.
Please
log in
or
register
to answer this question.
1
Answer
4
votes
cos x = -12/13
sin x = -sqrt(13^2 - 12^2) / 13 = -5/13
tan x = 5/12
tan x/2 = (1 - cos x) / sin x = 1 - (-12/13) / -5/13 = 25/13 * -13/5 = -5
2sin^2 x/2 = 1 - cos x = 1 - (-12/13) = 25/13
sin^2 x/2 = 25/13 / 2 = 25/26
sin x/2 = 5/√26
sin x/2 / cos x/2 = tan x/2
cos x/2 = sin x/2 / tan x/2 = 5/√26 / -5 = -1/√26
sin x/2 = 5/√26
cos x/2 = -1/√26
tan x/2 = -5
Mike Brennan
answered
Nov 14, 2017
by
Mike Brennan
8.5k
points
ask related question
comment
share this
0 Comments
Please
log in
or
register
to add a comment.
← Prev Question
Next Question →
No related questions found
Ask a Question
Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.
9.4m
questions
12.2m
answers
Categories
All categories
Mathematics
(3.7m)
History
(955k)
English
(903k)
Biology
(716k)
Chemistry
(440k)
Physics
(405k)
Social Studies
(564k)
Advanced Placement
(27.5k)
SAT
(19.1k)
Geography
(146k)
Health
(283k)
Arts
(107k)
Business
(468k)
Computers & Tech
(195k)
French
(33.9k)
German
(4.9k)
Spanish
(174k)
Medicine
(125k)
Law
(53.4k)
Engineering
(74.2k)
Other Questions
How do you can you solve this problem 37 + y = 87; y =
How do you estimate of 4 5/8 X 1/3
A bathtub is being filled with water. After 3 minutes 4/5 of the tub is full. Assuming the rate is constant, how much longer will it take to fill the tub?
Twitter
WhatsApp
Facebook
Reddit
LinkedIn
Email
Link Copied!
Copy
Search Qammunity.org