Hi,
I need a little help with an equation I got for math. It is as following:
sinē (x) . Cosē (y) + cosē (x) . Sinē (y) + sinē (x) . Sinē (y) + cosē (x) . Cosē (y) = 1
Now I tried to complete the exercise, but I got stuck. Let me show you what I did.
We know:
sin (x) . Cos (y) + cos (x) . Sin (y) = sin (x + y)
So I thought:
sinē (x) . Cosē (y) + cosē (x) . Sinē (y) = sinē (x + y)
Same for:
sin (x) . Sin (y) + cos (x) . Cos (y) = cos (x - y)
So I also thought:
sinē (x) . Sinē (y) + cosē (x) . Cosē (y)= cosē (x - y)
That gives us:
sinē (x+y) + cosē (x-y)
And that's where I got stuck. So anybody knows where I made an error / knows how I should continue?
Cheers,
A student