2·(^4π/8+^43π/8+^45π/8+^47π/8) ni hisoblang.

$\cos\frac{3\pi}{8}=\sin\frac{\pi}{8}$, $\sin\frac{5\pi}{8}=\cos\frac{\pi}{8}$, $\cos\frac{7\pi}{8}=-\cos\frac{\pi}{8}$. Qavs ichi $2\left(\sin^4\frac{\pi}{8}+\cos^4\frac{\pi}{8}\right)=2\left(1-\frac12\sin^2\frac{\pi}{4}\right)=\frac32$, demak ifoda $2\cdot\frac32=3$.

Manba: UZBMB namunaviy test topshiriqlari (Milliy sertifikat, Matematika)