求(1/1-tan22.5°)-(1/1+tan22.5°)的值
问题描述:
求(1/1-tan22.5°)-(1/1+tan22.5°)的值
答
解:1/(1-tan22.5º)-1/(1+tan22.5º) =(1+tan22.5º-1+tan22.5º)/(1+tan22.5º)(1-tan22.5º)=2tan22.5°/(1-tan²22.5°)=tan(2x22.5º)=tan45º=1