- #1
Robin04
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Homework Statement
Calculate sin75 without calculator![/B]
Homework Equations
The Attempt at a Solution
I constructed a triangle with angles 15, 75 and 90 then I defined sin75 by the sides. In a previous exercise the task was the same but with tg15 and I used the result in this execise too.
I wrote the equation: tg15 = b/a and if I express b and put it in the Pythagorean theorem I get the right result. However, if I express a and put it in the Pythagorean theorem I got a wrong result and I don't know why is this happening. I looked through it and I haven't find any calculation error... The second way is a lot longer but I should work. :(
http://kepfeltoltes.hu/thumb/150902/IMG_0122_www.kepfeltoltes.hu_.jpghttp://kepfeltoltes.hu/thumb/150902/IMG_0123_www.kepfeltoltes.hu_.jpg
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