Question 1079467
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If *[tex \Large \cos(s)\ =\ \frac{12}{13}] then *[tex \Large \cos^2(s)\ =\ \frac{144}{169}].  Then *[tex \Large 1\ -\ \sin^2(s)\ =\ \frac{144}{169}], *[tex \Large \sin^2(s)\ =\ \frac{25}{169}], and finally *[tex \Large \sin(s)\ =\ \pm\frac{5}{13}]


Similarly, from *[tex \Large \sin(t)\ =\ \frac{4}{5}] you can derive *[tex \Large \cos(t)\ \pm\frac{3}{5}]


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ \sin(s\ +\ t)\ =\ \sin(s)\cos(t)\ +\ \sin(t)\cos(s)]


Plug in the numbers and do the arithmetic. You will get two solutions because *[tex \Large \sin(s)\cos(t)] will be one sign or the other depending on the signs of *[tex \Large \sin(s)] and *[tex \Large \cos(t)]


John
*[tex \LARGE e^{i\pi}\ +\ 1\ =\ 0]
My calculator said it, I believe it, that settles it
<img src="http://c0rk.blogs.com/gr0undzer0/darwin-fish.jpg">
*[tex \Large \ \
*[tex \LARGE \ \ \ \ \ \ \ \ \ \  


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