The above series is an A.P. with a = 18, d = Let nth term be last term so, a n = We know that a n = a + (n - 1)d Using formula S n = Hence, the sum of the A.P. is -441.

The angles of a quadrilateral are in A.P. If the greatest angle is double of the smallest angle, find all the four angles.

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Find the sum of first 20 terms of an A.P. whose nth term is 15 - 4n.

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Solve the equation 2 + 5 + 8 + …. + x = 155.

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Mathematics

Find the sum : .

AP GP

Related Questions

The angles of a quadrilateral are in A.P. If the greatest angle is double of the smallest angle, find all the four angles.

Find the sum of first 20 terms of an A.P. whose nth term is 15 - 4n.

Solve the equation 2 + 5 + 8 + …. + x = 155.