(b) Given, $n! < \left( \ \frac{n + 1}{2} \right)^{n}$ At $n = 1$, $1! \nless 1$ At $n = 2,$ $2! < \left( \frac{3}{2} \right)^{2}$ $\Rightarrow 2 < 2.25$ which is true.
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.