If `costheta=1/2(a+1/a),cos3theta=lambda(a^3+1/(a^3)),t h e nlambda=` (a)`-1/4` (b) `1/4` (c) 1 (d) none of these

If cos theta=(1)/(2)(a+(1)/(a)),cos3 theta=lambda(a^(3)+(1)/(a^(3))), then lambda(a)-(1)/(4) (b) (1)/(4) (c) 1 (d) none of these

If costheta=1/2(a+1/a), show that : cos3theta=1/2(a^3+1/a^3)

costheta.cos2theta.cos3theta=1/4

If a : b=3:4, then 4a :3b= (a) 4:3 (b) 3:4 (c) 1:1 (d) None of these

If tan(pi//4+theta)+""tan(pi//4-theta)=lambdasec2theta,t h e nlambda= (a) 3 (b) 4 (c) 1 (d) 2

If x y-(log)_e y=1 satisfies the equation x(y y_2+y1 2)-y_2+lambday y_1=0,t h e nlambda= -3 (b) 1 (c) 3 (d) none of these

If cos e c^2theta(1+costheta)(1-costheta)=lambda , then find the value of lambda .

If x/(costheta)=y/(cos(theta-(2pi)/3))=z/(cos(theta+(2pi)/3)) then x+y+z is (a)1 (b) 0 (c) -1 (d) none of these

1/((2 1/3))+1/((1 3/4)) is equal to (a) 7/(14) (b) (12)/(49) (c) 4 1/(12) (d) None of these