Prove that: `t a n 70^0=t a n 20^0+2t a n 50^0dot`

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 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

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

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.

If sintheta=-1/2a n d t a ntheta=1/(sqrt(3))t h e n theta s equal to- 30^0 b.150^0 c.210^0 d.none of these

In a harmonic progression t_(1), t_(2), t_(3),……………., it is given that t_(5)=20 and t_(6)=50 . If S_(n) denotes the sum of first n terms of this, then the value of n for which S_(n) is maximum is

Let T(n) denotes the number of non-congruent triangles with integer side lengths and primeter n.Thus T(1)=T(2)=T(3)=T(4)=0, while T(5)=1. Prove that: (i) T(2006)

(bsecB+csecC)/(tanB+t a n C)=(csecC+csecC)/(tanC+t a n A)=(asecA+bsecB)/(tanA+t a n B)dot