angle sum formulasの例文

例文携帯版

I've always been told the sine and cosine angle sum formulas without any reason as to why they are true.
In this case the angle sum formula simplifies to 180? which we know is what Euclidean geometry tells us for triangles on a flat surface.
Using standard trig identities, in particular the angle sum formulas and the pythagorean theorem, you can get an algebraic formula for the sine of a whole angle in terms of the sine of one nth that angle, and likewise for cosine.
From the above angle sum formula we can also see that the Earth's surface is locally flat : If we draw an arbitrarily small triangle in the neighborhood of one point on the Earth's surface, the fraction " f " of the Earth's surface which is enclosed by the triangle will be arbitrarily close to zero.