" 2."sin75^(@)+sin15^(@)=(sqrt(6))/(2)" ."

sin 75^(@) + sin 15^(@) =

Show that sin^(2) 75^(@) - sin^(2) 15^(@) = (sqrt(3))/(2)

Prove that (i) " 2 cos " 45^(@) " cos " 15^(@)=((sqrt(3)+1))/(2) " "(ii) 2 " sin " 75^(@) " sin " 15^(@)=(1)/(2) (iii) " cos " 15^(@) - " sin " 15 =(1)/(sqrt(2))

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

sin^2 75^@-sin^2 15^@ =

sin^(2) 75^(@) - sin^(2)15^(@)=

Prove that : (i) "sin"105^(@)+cos105^(@)=(1)/(sqrt(2)) (ii) cos105^(@)+cos15^(@)="sin"75^(@)-"sin"15^(@)

Prove : cos15^(@) - sin15^(@) = 1//sqrt2 .

sin75^(@)-sin15^(@)=cos105^(@)+cos15^(@)

Prove that (i) " sin " 75^(@) =((sqrt(6)+sqrt(2)))/(4) (ii) (cos 135^(@) -cos 120^(@))/(cos 135^(@) +cos 120^(@)) =(3 -2sqrt(2)) (iii) " tan " 15^(@) +" cot " 15^(@) =4