Question

If first second and last terms of an A.P. are x, y
and z respectively, then prove that the sum of this series is
(x +z)(y+z-2x)/
2(y-x)
​

Answer 1

Answer:

Step-by-step explanation:

x , y ..........z

d = y - x

a = x

sum = n / 2 [ first + last ]

= n / 2 [ x + z ]

Tn = a + ( n - 1 ) d

z = x + ( n - 1 ) y-x

z- x / y - x = n - 1

n = z - x / y- x +1

n = z - x + y - x  / y-x

n = z + y -2x / y-x

so sum = (x +z) (y + z-2 x) /  2 (y - x)

Answer 2

Step-by-step explanation:

Answer

(x + z) (y + z - 2x) /2(y - x)