- Home
- Std 11
- Mathematics
8. Sequences and Series
easy
यदि $3 + 3\alpha + 3{\alpha ^2} + .........\infty = \frac{{45}}{8}$, तो $\alpha $ का मान होगा
A
$15/23$
B
$7/15$
C
$7/8$
D
$15/7$
Solution
(b) $3 + 3\alpha + 3{\alpha ^2} + 3{\alpha ^3} + …………..\infty = \frac{{45}}{8}$
$ \Rightarrow $ $3\left[ {\frac{1}{{1 – \alpha }}} \right] = \frac{{45}}{8}$
$ \Rightarrow $$8 = 15(1 – \alpha )$
$ \Rightarrow $$\alpha = \frac{7}{{15}}$.
Std 11
Mathematics
