(1)/(15+sqrt(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) "cos " 15^(@) - " sin " 15^(@) = (1)/(sqrt(2)) (ii) " cot " 105^(@) - " tan " 105^(@) =2sqrt(3) (iii) (tan 69^(@) + tan 66^(@))/(1-tan 69^(@) tan 66^(@)) =-1

the value of 3(1)/(sqrt(2)+1)+(1)/(sqrt(3)+sqrt(2))+(1)/(sqrt(4)+sqrt(3))+.........+(1)/(sqrt(16)+sqrt(15)) is

4sin^(3)75^(0)-3cos15^(0)= (1)/(2) (1)/(sqrt(2)) (1)/(sqrt(3)) sqrt(3)

Prove that: sin15^(@)=(sqrt(3)-1)/(2sqrt(2))

Prove that: sin15^(@)=(sqrt(3)-1)/(2sqrt(2))

The value of cos 15^(@) - sin 15^(@) is equal to .................. A) (1)/(sqrt2) B) (1)/(2) C) -(1)/(sqrt2) D) 0

Let y=(1)/(2+(1)/(1+(1)/(2+(1)/(2+(1)/(1+(1)/(1)))))), then the value of y is a.(sqrt(3)-1)/(2) b.(2)/(sqrt(15)+3) c.(sqrt(15)+3)/(2)d(1)/(sqrt(3)+1)