`cos 40^(@)=0.76` then `sin 50^(@)`=………….

if sin50^(@)=0.766, then sec40^(@)=

(sin 70^(@) + cos 40^(@))/(cos 70^(@) + sin 40^(@)) =

(sin 70^(@) + cos 40^(@))/(cos 70^(@) + sin 40^(@))=

(sin 70^(@) + cos 40^(@))/(cos 70^(@) + sin 40^(@))=

Evaluate cos 40 ^(@) cosec 50 ^(@)+ sin 50 ^(@) sec 40 ^(@)

Simplify cos 100^(@) cos 40^(@) + sin 100^(@) sin 40^(@) .

( sin 70^(@) + cos 40^(@) )/( cos 70^(@) + sin 40^(@))=

cos (40^@ + theta) - sin (50^@ - theta) is equal to

Simplify cos 100^(@) cos 40^(@) +sin 100^(@) sin 40^(@)

Prove that (i) " sin " 80^(@) "cos " 20^(@) - " cos " 80^(@) " sin " 20^(@) =(sqrt(3))/(2) (ii) " cos " 45^(@) " cos " 15^(@) - " sin " 45^(@) " sin " 15^(@) = (1)/(2) (iii) " cos " 75^(@) " cos " 15^(@) + " sin " 75^(@) " sin " 15^(2)= (1)/(2) (iv) " sin " 40^(@) " cos " 20^(@) " + cos " 40^(@) " sin " 20^(@) =(sqrt(3))/(2) (v) " cos " 130^(@) " cos " 40^(@) l + " sin " 130^(@) " sin " 40^(@) =0