1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Need some clarification in regards to trigonometry

  1. Jun 4, 2008 #1

    r6mikey

    User Avatar

    Need some clarification in regards to trigonometry....

    1. The problem statement, all variables and given/known data

    For some reason, I am not seeing the cause of this. In attached problem 1, the Forces of x are described with a cos while forces of y are described with sin. In the second problem, the forces of X use sin and the forces of y use cos...... What am I missing here? Is there a certain topic I can review? Is it because of the quadrants they are in? the triangle they make (I would think obviously, I just don't see it :( )


    Some of problem 1 has been cut off so I could attach the files

    2. Relevant equations

    How do I figure out if I'm suppose to use a cos or a sin for x or y?
     

    Attached Files:

    r6mikey, Jun 4, 2008
  2. jcsd
    Phys.org - latest science and technology news stories on Phys.org
  3. Jun 4, 2008 #2

    fantispug

    User Avatar

    I can't see your images yet, but I'm going to guess the problem is which angle you are using:



    Consider a right angle triangle, with sides x, y and hypotenuse 1 (draw it!). Let's take the angle t to be between the sides x and 1: then cos(t)=adjacent/hypotenuse=x
    sin(t)=opposite/hypotenuse=y

    But if we take s to be the angle between 1 and y
    cos(s)=adjacent/hypotenuse=x
    sin(s)=opposite/hypotenuse=y

    Does that answer your question?
     
    fantispug, Jun 4, 2008
  4. Jun 5, 2008 #3

    tiny-tim

    User Avatar
    Science Advisor
    Homework Helper

    Hi r6mikey! :smile:

    Forget about triangles.

    The component in a direction is always found by multiplying by the cos of the angle between.

    (so you only use sin if it's the "wrong" angle! :biggrin: )
     
    tiny-tim, Jun 5, 2008
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Need some clarification in regards to trigonometry

  1. Need Help regarding some problems (Replies: 18)

  2. Just need some clarification (Replies: 4)

  3. I need some clarification Thermo Cycle (Replies: 1)

  4. Moment of force ? some clarifications needed. (Replies: 7)

  5. Need some clarification on conducting spheres (Replies: 3)

Loading...