Question

If mth term of an ap is n and nth term is m find the sum of mn term is 1/2(mn+1)

Answer 1

sorry it is upside down

hope it helps

Answer 2

Answer:

$a + (m)d = \frac{1}{m} \\ \\ a + (m)d = \frac{1}{n} \\ \\ \frac{1}{n} - \frac{1}{m} = (m + 1 - n - 1) \\ \\ \frac{m - n}{mn} = (m + n)d \\ \\ (d = \frac{1}{mn})(a = \frac{1}{mn}) \\ \\ mn = a + (mn - 1)d \\ \\ \frac{1}{mn} + \frac{mn - 1}{mn} = 1$[/tex]