63. cosα=4/5 ga teng. sin2α ni hisoblang.

\(\sin\alpha=\sqrt{1-\left(\frac45\right)^2}=\frac35\). Shuning uchun \(\sin2\alpha=2\cdot\frac35\cdot\frac45=\frac{24}{25}\).

Javob: \(\frac{24}{25}\) (D).