6. Consider two G.P.'s. 2, 22, 23, and 4, 4, 4, of 60 and n terms respectively. If the 225 n geometric mean of all the 60 + n terms is (2), then k(n-k) is equal to: (a) 560 (b) 1540 (c) 1330 (d) 2600 7. If the function f(x) = 0, then k is equal to: log. (1-x+x)+log. (1+x+x) sec x-cos x k xe (0) is continuous at x= (a) 1 (b) -1 8. If f(x) = (x+a, x0 ||x-4, x>0 and g(x)= (x+1) (x-4)+b, x0 ,x 1 .Then the set of all values of b, for which f(x) has maximum value at x = 1, is: (a) (-6,-2) (d) [-6,-2) (2,6] (b) (2,6) (d) [-6,-2)(2,6] 2n 10. If a lim and f(x) = 1-cos x 1+cosx () 2421 (c) (a) 22f n+k 9-9 0-9 shik -0-20 x = (0, 1), then: b) ff-2