Q7 of 89 Page 56

Show that the sum of an AP whose first term is a, the second term b and the last term c, is equal to

Given that, the AP is a, b, …, c.


Here, first term = a


common difference = b - a


and last term, an = c


as nth term of an AP


an = a + (n - 1)d






[ eqn 1]


Sum of an AP




So



Hence Proved.


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