6. If cos' x sin 2x = a, sin(rx), VXER then 1 A. n= 5, a, = 2 B. n = 5, a, = - C. n= 5, a, =- D. n = 5, a, = B 7. If, cose= a cos+b then tan 812 is equal to a +b coso D. none of these a +b cos(/2) a -b tan(/2) + b . Va + b sin(/2) A. . Ttr 8. The value of > cos is equal to (A) (C) 9. If 2 sec 2 a = tan B+ cot B, then one positive value of a +B is a) 2 b) 4 d) 0 10. The value of sin' 10" + sin' 50" sin' 70 is equal to a) b) 4 sin 23 If tan (a - pB) = then 3-cos 26 11. a) tan a = 2 tan B b) tan B= 2 tan a c) 2 tan a = 3 tan B d) 3 tan a = 2 tan B 12. In a triangle ABC, if angle C is obtuse and angles A and B are given by roots of the equation tanx +p tanx + q = 0, then the value of q is b) less than 1 a) greater than 1 b c) equal to 1 d) 0 13. If 2sinx - cos2x = 1, then cos'x + cos*x is equal to a) 1 b) 1 c) -V5 d) V5