SOLUTION: sin(-55)

Question 594792: sin(-55)
Found 3 solutions by Alan3354, in_the_math_vortex, math-vortex:
Answer by Alan3354(69443)   (Show Source): You can put this solution on YOUR website!
sin(-55)
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You don't have a calculator?

Answer by in_the_math_vortex(4)   (Show Source): You can put this solution on YOUR website!

Answer by math-vortex(648)   (Show Source): You can put this solution on YOUR website!
Hi, there,
I will assume that you are working in degrees, and want to know the sine of a 55 degree angle. You can just type this expression into a calculator and get an approximation, but I'm guessing that you want to simplify it to the sine of positive angle.
We have:

Use an even/odd trigonometric identity to rewrite the expression. The sine function is odd, so sin(-x) = -sin(x). Therefore,

You can stop here with an exact answer, or use a calculator to get an approximation:
.
-sin(55) is approximately equal to -0.819152044.
.
Here is a link to a nice pdf "cheat sheet" of everything you ever wanted to know about trigonometric functions, identities, etc.
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http://tutorial.math.lamar.edu/pdf/Trig_Cheat_Sheet.pdf
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Hope this helps! Feel free to email me if you have questions about this solution.
.
Mrs.Figgy
math.in.the.vortex@gmail.com

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