Suppose we are given an unsorted database with N items and N is sufficiently large. By using a simpler approximate method, we re-derive the approximate formula cos Φ, which represents the maximum success probability of Grover's algorithm corresponding to the case of identical rotation angles $${\phi=\theta}$$ for any fixed deflection angle $${\Phi \in\left[0,\pi/2\right)}$$. We further show that for any fixed $${\Phi \in\left[0,\pi/2\right)}$$, the case of identical rotation angles $${\phi=\theta}$$ is energetically favorable compared to the case $${\left|{\theta - \phi}\right|\gg 0}$$ for enhancing the probability of measuring a unique desired state. [ABSTRACT FROM AUTHOR]