2.4+4.7+6.10+….(n-1) terms=
2n3-2n2
(n3+3n2+1)/6
2n3+2n
none
If 23+43+63+….+(2n)3=kn2(n+1)2, then k=
1/2
1
3/2
2
12+32+52+…+(2n-1)2=
n(2n-1)(2n+1)/3
n(2n+1)(2n+1)/3
(2n-1)(2n-1)/3
1+4+10+19+….(3n2-3n+2)/2=
n(n+1)(2n+1)/6
n2(n+1)2/4
n(n+1)(n+2)/6
n(n2+1)/2
If nεN then 10n+3.4n+2+5 is divisible by
3
8
9
11
If nεN then 3.52n+1+23n+1 is divisible by
24
64
17
676
(1/1.3)+(1/3.5)+(1/5.7)+….n terms=
1/n+1
n/n+1
n/2n+1
n/3n+1
1.22+2.32+3/42+….n(n+1)2/12.2+22.3+32.4+…n2(n+1)=
3n+5/3n+1
3n+1/3n+5
(3n+1)(3n+5)
(12/3)+(12+22/5)+(12+22+32/7)+… n terms
n(n+1)(n+2)/18
n(n+1)(n+2)/3
2n(n+1)(n+2)/3
1+4+13+40+…n terms=
3n+1-2n/2n
(3n+1-2n-3)/4
3n-1+3n/9
(3n+1+2n2)/8
Sum of n brackets of (1)+(1/3+1/32)+(1/33+1/34+1/35)+…. Is
(3n-1)3/2.4n-1
(3n-1)/2.3 (n-1)(n+2)/2
(3n+1)/3.7n-1
The equation of lines passing through the intersection of lines x-2y+5=0 and 3x+2y+7=0 and perpendicular to x-y=0 is
x + y = 0
x + y = 2
x + y + 2=0
x + y +1=0
102n+1+1 for all n?N is divisible by
7
The area bounded by y = 3x and y = x2 is (in sq units)
10
5
4.5
13+23+ 33+….+1003=k2, then k=
10100
5000
5050
1010
(1)+(2+3+4)+(5+6+7+8+9)+… n brackets=
n2(n2+1)/2
n(n+1)(n+2)
∑((12+22+32+….+n2)/1+2+3+….+n)=
(n2+2n)/3
n2-2n/6
n2+11/12n
1.4.7+4.7.10+7.10.13+…. n terms
n(n+1)(3n2+23n+46)/12
n(27n3+90n2+45n-50)/4
(1)+(2+3)+(4+5+6)+….n brackets=
n(n+1)(n2+n+2)/8
n(n+1)(n2-n+2)/8
n(n-1)(n2+n+2)/8
n(n-1)(n2-n+2)/8
(1)+(1+2)+(1+2+3)+…. n brackets=
1.2+2.3+3.4+….n terms
n(n+1)(n+5)/3
n(4n2+6n-1)/3
(14/1.3)+(24/3.5)+(34/5.7)+….+n4/(2n+1)(2n-1)=
n(n+1)(n+2)/6n
n(n+1)(n2+n+1)/6(2n+1)
n(n+2)(n+3)2
2+3+5+6+8+9+…..2n terms=
3n2+2n
4n2+2n
4n2
1.3.4+2.4.5+3.5.6+…. n terms
13+12+1+ 23+22+2+ 33+32+3+…3n terms=
n(n+1)2
n2(n-1)
n(n+1)(3n2+7n+8)/12
The value of the sum in the n th bracket of (1)+(2+3)+(4+5+6+7)+(8+9+10+15)+… is
2n(2n+2n-1-1)
2n-1(2n+2n-1-1)
2n-2(2n+2n-1-1)
(13/1)+(13+23/1+3)+(13+23+33/1+3+5)+….. n terms
n(2n2+9n+13)/24
n(2n3+9n+13)/18
n(n2+9n+13)/24
n(n2+9n+13)/8
The sum of the first n terms of the series 12+2.22+32+2.42+52+2.62+…. Is n(n+1)2/2 when n is even. When n is odd the sum is
3n(n+1)/2
[n(n+1)/2]2
n(n+1)2/4
n2(n+1)/2
1.3+2.32+3.33+4.34+….+n.3n=
(2n-1)3n+1+3/4
(2n+1)3n+1+3/4
(2n+1)3n+1-3/4
(2n-1)3n+1-3/4
2.12+3.22+4.32+….+(n+1)n2=
n(n+1)(n+2)(3n+5)/12
n(n+1)(n+2)(n+3)/4
2n(n+1)(n+2)(n+3)
n(n+1)(n+2)(3n+1)/12