Prove that:
`(cos40^(@)+cos50^(@))/(sin40^(@)+sin50^(@))=1`

Prove that: i) sin40^(@)cos50^(@)+cos40^(@)sin50^(@)=1 ii) cot(270^(@)-theta)cot(270^(@)+theta)(cot(540^(@)-theta)cot(540^(@)+theta)=1 iii) cospi/8+cos(3pi)/8+cos(5pi)/8+cos(7pi)/8=0

Prove that: i) sin40^(@)cos50^(@)+cos40^(@)sin50^(@)=1 ii) cot(270^(@)-theta)cot(270^(@)+theta)(cot(540^(@)-theta)cot(540^(@)+theta)=1 iii) cospi/8+cos(3pi)/8+cos(5pi)/8+cos(7pi)/8=0

Prove that (sin70^(@)-cos40^(@))/(cos50^(@)-sin20^(@)) = 1/(sqrt(3)) .

(sin70^(@)+cos40^(@))/(cos70^(@)+sin40^(@))

(sin70^(@)+cos40^(@))/(cos70^(@)+sin40^(@))=

(sin70^(@)+cos40^(@))/(cos70^(@)+sin40^(@))=

(sin70^(@)+cos40^(@))/(cos70^(@)+sin40^(@))=?

cos70^(@)+sin40^(@)=

cos70^(@)+sin40^(@)=

Prove that cos 20^(@) cos 40^(@) - sin5^(@) sin 25^(@) = (sqrt(3)+1)/(4) .