Exact values of sin(30) and cos(3pi/2)

  • Thread starter cscott
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  • #1
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How can I work out exact values for trig functions like sin(30) and cos(3pi/2)?
 

Answers and Replies

  • #2
For simple expressions, use trigonometric/complex identities to reduce to terms you already know. For more complicated expressions, use series, ie., Taylor or Euler's expansions.
 
  • #3
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cscott said:
How can I work out exact values for trig functions like sin(30) and cos(3pi/2)?

Like the decimal values? Without a calculator?

I would just draw out the triangle and leave the answer in the exact radical form, like in your first example. But [itex]\cos{\frac{3\pi}{2}}[/itex] is 0 so that should be easy.
 
  • #4
782
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Ah thanks.
 

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