1. Zadatak

Kako je

$$\begin{aligned} \frac{\log_3 12+\log_4 12}{\log_3 12\cdot\log_4 12} &=\frac{\log_3 12}{\log_3 12\cdot\log_4 12}+\frac{\log_4 12}{\log_3 12\cdot\log_4 12}\\ &=\frac1{\log_4 12}+\frac1{\log_3 12}\\ &=\log_{12}4+\log_{12}3\\ &=\log_{12}12\\ &=1, \end{aligned}$$

tražena vrijednost iznosi

$$\cos(2025\pi)=-1.$$