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

Trigonometric equations with sin and cot

  • Thread starter dbg11
  • Start date
  • #1
1
0

Homework Statement


find the value(s): cot(2sin^(-1) 2/7)



The Attempt at a Solution



I solved for sine by drawing a unit circle and the angle. I used the given values of 2 for the y value and 7 for the r value(hypotenuse). By using the pythagorean theorem I found the x value which, for me, came out to 4 sqrt(3). From the x value I was able to find the cosine. Since cotangeant is cosine/ sine I solved for that to get my exact value but it did not come out to the correct answer.
I think it had something to do with the (2 sin) in the equation. I am not sure exactly what to do when an equation gives me a number times sine.
 
Last edited by a moderator:

Answers and Replies

  • #2
[itex]\frac{1}{tan(\frac{2}{sin(2/7)})}[/itex] ?
 
  • #3
33,639
5,301

Homework Statement


find the value(s): cot(2sin^(-1) 2/7)



The Attempt at a Solution



I solved for sine by drawing a unit circle and the angle. I used the given values of 2 for the y value and 7 for the r value(hypotenuse). By using the pythagorean theorem I found the x value which, for me, came out to 4 sqrt(3).
I get 3√5, not 4√3.
From the x value I was able to find the cosine. Since cotangeant is cosine/ sine I solved for that to get my exact value but it did not come out to the correct answer.
I think it had something to do with the (2 sin) in the equation. I am not sure exactly what to do when an equation gives me a number times sine.
 

Related Threads on Trigonometric equations with sin and cot

Replies
1
Views
522
Replies
1
Views
922
  • Last Post
Replies
2
Views
1K
Replies
6
Views
1K
Replies
3
Views
968
Replies
1
Views
826
Replies
4
Views
582
  • Last Post
Replies
3
Views
2K
  • Last Post
Replies
5
Views
717
Top