If `cos28^0+sin28^0=k^3, t h e ncos17^0` is equal to (a)`(k^3)/(sqrt(2))` (b) `-(k^3)/(sqrt(2))` (c) `+-(k^3)/(sqrt(2))` (d) none of these

If cos28^0+sin28^0=k^3, t h e ncos17^0 is equal to (k^3)/(sqrt(2)) (b) -(k^3)/(sqrt(2)) (c) +-(k^3)/(sqrt(2)) (d) none of these

If |cos^(-1)((1-x^2)/(1+x^2))| < pi/3,t h e n (a) x in [-1/3,1/(sqrt(3))] (b) x in [-1/(sqrt(3)),1/(sqrt(3))] x in [0,1/(sqrt(3))] (d) none of these

The value of ("lim")_(xvec2)(sqrt(1+sqrt(2+x))-sqrt(3))/(x-2)i s (a) 1/(8sqrt(3)) (b) 1/(4sqrt(3)) (c) 0 (d) none of these

If y=|cosx|+|sinx|,t h e n(dy)/(dx)a tx=(2pi)/3 is (1-sqrt(3))/2 (b) 0 (c) 1/2(sqrt(3)-1) (d) none of these

If alpha,beta,gamma,delta are the smallest positive angles in ascending order of magnitude which have their sines equal to the positive quantity k , then the value of 4sin(alpha/2)+3sin(beta/2)+2sin(gamma/2)+sin(delta/2) is equal to (a) 2sqrt(1-k) (b) 2sqrt(1+k) (c) (sqrt(1-k))/2 (d) none of these

If tan^(-1)(a+x)/a+tan^(-1)(a-x)/a=pi/6,t h e nx^2= 2sqrt(3)a (b) sqrt(3)a (c) 2sqrt(3)a^2 (d) none of these

If int_(pi/4)^((3pi)/4) x/(1+sinx)dx=k(sqrt(2)-1) , then k = (A) 0 (B) pi (C) 2pi (D) none of these

If (tan3A)/(tanA)=k(k!=1) then which of the following is not true? (a) (cosA)/(cos3A)=(k-1)/2 (b) (sin3A)/(sinA)=(2k)/(k-1) (c) (cot3A)/(cotA)=1/k (d) none of these

sin{2(sin^(-1)(sqrt(5))/3-cos^(-1)(sqrt(5))/3)} is equal to (ksqrt(5))/(81) then k=

sin{2(sin^(-1)(sqrt(5))/3-cos^(-1)(sqrt(5))/3)} is equal to (ksqrt(5))/(81) then k=