tan1°=tan(90°-89°)=ctan89°tan2°=ctan88°.tan44°=ctan46°tan45°=1所以,tan1°×tan2°×tan3°×tan4°×tan5°×……×tan87°×tan88°×tan89° =tan89°×ctan89°×tan88°×ctan88°×...tan46°×c...