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You can verify the identity by expanding each term using the formula above and doing Good luck!
Hi James. You are looking for the "inverse function" of this. T = n(n+1)/2 Now remember the quadratic formula: Since we don't care about the negative roots, we just use plus instead of plusorminus. Let's simplify the quadratic formula using what we know from 0 = n² + n  2T n = [(1)+√([1]²4[1][2T])] / (2[1]) So there you have it. The inverse equation is For example, if the total T is 15, then n is calculated: Cheers,  


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