The value of `1/6+1/(12)+1/(20)+...1/(90)` is (A)`1/5` (B) `2/5` (C) `3/5` (D) None of these

The value of (1)/(6)+(1)/(12)+(1)/(20)+......+(1)/(90) is: (A) (1)/(5)(B)(2)/(5)(C)(3)/(5) ( textrmD ) none of these

Find the value of (( 2^0 + 1)/ 5^0 ) is ( a ) 2 ( b ) 1 ( c ) ( 2/5 ) ( d ) ( 3/5 )

If z=1/((2+3i)^2), then |z| is (a) . 1/13 (b) . 1/5 (c) . 1/12 (d) . none of these

The value of tan[cos^(-1)(4/5)+tan^(-1)(2/3)] is 6/(17) (b) 17/(6) (c) (16)/7 (d) none of these

The value of tan[cos^(-1)(4/5)+tan^(-1)(2/3)] is 6/(17) (b) 7/(16) (c) (16)/7 (d) none of these

The value of tan[cos^(-1)(4/5)+tan^(-1)(2/3)] is 6/(17) (b) 7/(16) (c) (16)/7 (d) none of these

The value of tan[cos^(-1)(4/5)+tan^(-1)(2/3)] is 6/(17) (b) 7/(16) (c) (16)/7 (d) none of these

If a=sum_(r=1)^oo(1/r)^2, b=sum_(r=1)^oo1/((2r-1)^2), then a/b= (A) 5/4 (B) 4/5 (C) 3/4 (D) none of these

If a=sum_(r=1)^oo(1/r)^2, b=sum_(r=1)^oo1/((2r-1)^2), then a/b= (A) 5/4 (B) 4/5 (C) 3/4 (D) none of these

The value of 3^((log)_4 5)-5^((log)_4 3) is 0 (b) 1 (c) 2 (d) none of these