Trig Functions- Could anyone tell me why my working is wrong?

Click For Summary
SUMMARY

The discussion centers on solving the trigonometric equation 2cos(x) - (√3)cos(x)sin(x) = 0 within the interval (-π, π). The initial approach of dividing by cos(x) led to an incorrect conclusion that sin(x) = 2/√3, which is not possible. The correct method involves factoring the equation to find cos(x) = 0, yielding the solutions x = π/2 and x = -π/2.

PREREQUISITES
  • Understanding of trigonometric identities and functions
  • Familiarity with solving equations involving trigonometric functions
  • Knowledge of the unit circle and the range of sine and cosine functions
  • Basic algebraic manipulation skills
NEXT STEPS
  • Study the properties of trigonometric functions and their ranges
  • Learn how to factor trigonometric equations effectively
  • Explore the unit circle to understand angles and their sine and cosine values
  • Practice solving a variety of trigonometric equations
USEFUL FOR

Students studying trigonometry, educators teaching trigonometric equations, and anyone looking to improve their problem-solving skills in trigonometric functions.

ku1005
Messages
66
Reaction score
0
Trig Functions- Could anyone tell me why my working is wrong??

the question seems simple..although i don't know what i am doing because it is obviously wrong!. thnkas heaps if anyone can help..

solve
2cosx-(sqrt(3))cosx sinx = 0 for (-pie<=x<=pie)

what i was doing is dividing through by cos x, therefore i obtain:

2-(sqrt(3))sinx= 0

however this statement is flawed! since no value exists for sin x= 2/(sqrt(3))

?it seems simple.. so wat am i doing wrong!1
 
Physics news on Phys.org
ku1005 said:
the question seems simple..although i don't know what i am doing because it is obviously wrong!. thnkas heaps if anyone can help..

solve
2cosx-(sqrt(3))cosx sinx = 0 for (-pie<=x<=pie)

what i was doing is dividing through by cos x, therefore i obtain:

2-(sqrt(3))sinx= 0

however this statement is flawed! since no value exists for sin x= 2/(sqrt(3))

?it seems simple.. so wat am i doing wrong!1

if you copied the question right then yes sin x = 2/srqt3 is not possible

however you CAN find answer for the cosine part
cos x = 0 what values of x will do?
 
yep got it now...instead i just did the follwing
=
cosx(2-(sqrt(3))sinx)=0
therfore either cosx= 0 (as u stated above) or the other applies...which isnlt possible...so yeah obviously the answers are pie/2 and -pie/2
thanks for your help!
 

Similar threads

  • · Replies 11 ·
Replies
11
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 7 ·
Replies
7
Views
2K
Replies
5
Views
3K
Replies
11
Views
36K
  • · Replies 15 ·
Replies
15
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 7 ·
Replies
7
Views
2K