Question

128 The sum of n terms of the series 5/2-1 + 2/5 - ......​

Answer 1

Answer:

(-23,-36) #gdhdgdggdgdhfhhDJfhhfhfhhfhfhhfhfhdh

Answer 2

Answer:

The series is in GP with C.R = -2/5

Sum of n terms =

$\frac{a(1 - {r}^{n} )}{1 - r} = \frac{ \frac{5}{2} \times (1 - ( - \frac{2}{5} ) {}^{n} )}{1 + \frac{2}{5} } = \frac{5}{7} \times \frac{5}{2} \times (1 - ( - \frac{2}{5} ) {}^{n} ) = \frac{25}{14} \times (1 - ( - \frac{2}{5} ) {}^{n} )$