We were given a sequence \( \left(2\cdot x^n\right)_{n=1}^{\infty} \).
For what values of the parameter \( x \), \( x\in\mathbb{R} \), is the sequence increasing?
We were given a sequence \( \left(\frac{n\cdot x}{n+1}\right)_{n=1}^{\infty} \).
For what values of the parameter \( x \), \(x\in\mathbb{R}\), is the sequence decreasing?
We were given two sequences \( \left( 2^{2n-2} \right)_{n=1}^{\infty} \) and \( \left( n^2 \right)_{n=1}^{\infty} \).
What is the ratio of their fourth terms?