Rearranging Trigonometric Functions

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SUMMARY

The discussion centers on the rearrangement of the trigonometric identity tanθ = sinθ/cosθ. The user confirms that the rearrangements sinθ = (tanθ)(cosθ) and cosθ = sinθ/tanθ are valid. The participants agree that while these variations are numerically correct, they may not frequently appear in practical applications. The conversation emphasizes understanding the foundational definitions of sine, cosine, and tangent to facilitate remembering these relationships.

PREREQUISITES
  • Understanding of basic trigonometric functions: sine, cosine, and tangent.
  • Familiarity with trigonometric identities and their rearrangements.
  • Knowledge of right triangle properties and relationships.
  • Basic algebra skills for manipulating equations.
NEXT STEPS
  • Study the derivation of trigonometric identities and their applications.
  • Learn about the unit circle and its role in defining trigonometric functions.
  • Explore practical applications of trigonometric functions in physics, particularly in mechanics.
  • Practice solving problems involving the rearrangement of trigonometric equations.
USEFUL FOR

Students studying physics or mathematics, particularly those focusing on trigonometry and its applications in mechanics and geometry.

talknerdy2me
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This is my very first post - so i hope I don't break any rules - its more of a formula rearranging question/confirmation so here goes...

Homework Statement


Currently working on friction - static/kinetic - so in my textbook it states in a side bar "info bit" that

tanθ=sinθ/cosθ my question is : can this equation be rearranged - see below...


Homework Equations



so if tanθ=sinθ/cosθ then does sinθ=(tanθ)(cosθ) and does cosθ=sinθ/tanθ


The Attempt at a Solution



I haven't come across any questions so far where i would need to use sinθ=(tanθ)(cosθ) and cosθ=sinθ/tanθ - more or less a general question of would I encounter having to use the sinθ=(tanθ)(cosθ) and cosθ=sinθ/tanθ rather than tanθ=sinθ/cosθ - numerically it works, but are these variations used?


Hope this wasn't clear as mud... If i can provide any more info - let me know!

:bugeye:
 
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Hello talknerdy2me,

Welcome to Physics Forums! :smile:

talknerdy2me said:
This is my very first post - so i hope I don't break any rules - its more of a formula rearranging question/confirmation so here goes...

Homework Statement


Currently working on friction - static/kinetic - so in my textbook it states in a side bar "info bit" that

tanθ=sinθ/cosθ my question is : can this equation be rearranged - see below...
Yes.

Homework Equations



so if tanθ=sinθ/cosθ then does sinθ=(tanθ)(cosθ) and does cosθ=sinθ/tanθ
Yep. You got it. :smile:

The Attempt at a Solution



I haven't come across any questions so far where i would need to use sinθ=(tanθ)(cosθ) and cosθ=sinθ/tanθ - more or less a general question of would I encounter having to use the sinθ=(tanθ)(cosθ) and cosθ=sinθ/tanθ rather than tanθ=sinθ/cosθ - numerically it works, but are these variations used?


Hope this wasn't clear as mud... If i can provide any more info - let me know!

:bugeye:

If it helps, this might make it a little more easy to remember:

\sin \theta = \frac{\text{opposite}}{\text{hypotenuse}}
\cos \theta = \frac{\text{adjacent}}{\text{hypotenuse}}
\tan \theta = \frac{\text{opposite}}{\text{adjacent}}
If you can remember those, the other relationships you mentioned above should fall into place.
 
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