Question

find the value 1+2+3+4+5+6+7+8+9+..........................45?​

Answer 1

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1035

step-by-step explanation :

we have to find the sum of

1+2+3+4+..........................+45

Looking the sequence,

we come to know that,

we have to find the sum of first 45 natural numbers.

Now,

we know that,

sum of n natural numbers = n(n+1)/2

Here,

n = 45

putting the value of n= 45 in the abive formula,

we get,

sum = 45 × (45+1)/2

= 45 × 46/2

= 45 × 23

= 1035

Hence,

1+2+3+4+............+45 = 1035

Answer 2

Let the first term be a = 1.

The common difference be d = 1.

The number of terms be l = 45.

So, sum of 45 terms = n/2{2a+(n-1)d}

S45 = 45/2{2+44(1)}

= 45/2(46)

= 45*23

= 1035

Hope this helps..