[" cill "(1)/(2a+b+2n)=(1)/(2a)+(1)/(b)+(1)/(2n)]

The arithmetic mean of 1,2,3,...n is (a) (n+1)/(2) (b) (n-1)/(2) (c) (n)/(2)(d)(n)/(2)+1

The value of int_(-pi//2)^(pi//2)sqrt(cos^(2n-1)x-cos^(2n+1)x)dx,n in N , is a) (4)/(2n+1) b) (1)/(2n+1) c) (2)/(2n+1) d) (1)/(2(2n+1))

If b_(1),b_(2),b_(3),"….."b_(n) are positive then the least value of (b_(1) + b_(2) +b _(3) + "….." + b_(n)) ((1)/(b_(1)) + (1)/(b_(2)) + "….." +(1)/(b_(n))) is

The sum to infinity of the series 1+2(1-(1)/(n))+3(1-(1)/(n))^(2)+ . . .. . . . , is (A) n^(2) (B) n(n+1) (C) n(1+(1)/(n))^(2) (D)None of these

The sum to infinity of the series 1+2(1-(1)/(n))+3(1-(1)/(n))^(2)+ . . .. . . . , is (A) n^(2) (B) n(n+1) (C) n(1+(1)/(n))^(2) (D)None of these

(lim_(n rarr oo)[(2n)/(2n^(2)-1)(cos(n+1))/(2n-1)-(n)/(1-2n)(n(-1)^(n))/(n^(2)+1)]is1(b)-1(c)0(d) none of these

The mean deviation of the series a , a+d , a+2d ,.....,a+2n from its mean is (a) ((n+1)d)/(2n+1) (b) (n d)/(2n+1) (c) (n(n+1)d)/(2n+1) (d) ((2n+1)d)/(n(n+1))

The mean deviation of the series a , a+d , a+2d , , a+2n from its mean is ((n+1)d)/(2n+1) (b) (n d)/(2n+1) (c) (n(n+1)d)/(2n+1) (d) ((2n+1)d)/(n(n+1))

The mean deviation of the series a , a+d , a+2d ,.....,a+2nd from its mean is (a) ((n+1)d)/(2n+1) (b) (n d)/(2n+1) (c) (n(n+1)d)/(2n+1) (d) ((2n+1)d)/(n(n+1))