Question

2+3+4+-------+(n-1)=​

Answer 1

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Answer 2

Answer:

Here's your answer

Step-by-step explanation:

As I know the formula for adding 1,2,3…n is given by n(n+1)/2

Comparing to above formula if we want to calculate sum up to n-1 , using the above formula we get n-1(n-1+1)/2

That is n(n-1)/2

Thus the required formula is n(n-1)/2

Hope it helps you

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