Prove that

sinē x + cosē x = 1

If you take the right angled triangle ABC (Where b is a right angle and C = x) then
sin^2 x = AB^2/AC^2
cos^2 x = BC^2/AC^2

Therefore sin^2 x + cos^2 = (AB^2 + BC^2)/AC^2

But AB^2 + BC^2 = AC^2 (Pythogorean Thoerem)

Through substituition AC^2/AC^2 = 1

So sin^2 x + cos^2 = 1

Posted by Chaz on 2003-05-03 02:53:36