Prove that `:(tan69^0+t a n 66^0)/(1-t a n 69^0t a n\ 66^0)=-1`

Prove that :(tan69^(@)+tan66^(@))/(1-tan69^(@)tan66^(@))=-1

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

Prove that:(i) "tan"69^(@)+"tan"66^(@)+1="tan"69^(@) "tan"66^(@) (ii) (cos13^(@)+"sin"13^(@))/(cos13^(@)-"sin"13^(@))="tan"58^(@)

Prove that: tan6^(0)tan42^(0)tan66^(@)tan78^(@)=1

Value of (cos 12^0+s in 12^0)/(cos 12^0-s in 12^0) is equal to t a n 417^0 b. t a n 237^0 c. t a n 57^0 d. t a n 663^0

If tan69+tan66-tan69tan66=2k then k=

If (1+t a n1^0)dot(1+t a n2^0)dot(1+t a n3^0)(1+tan45^0)=2^n , then ' n ' is equal to 16 b. 23 c. 3 0 d. none of these

If A+B+C=180^0 , then (t a n A+t a n B+t a n C)/(t a n A t a n B t a n C) is equal to t a n A t a n B t a n C b. 0 c. 1 d. none of these

Prove that t^(2) + 3t + 3 is a factor of ( t+1)^(n+1) + (t+2)^(2n -1) for all intergral values of n in N.

Solve the inequality : tan^2x-(sqrt(3)+1)\ t a n x+sqrt(3)<0