tan945的精选

问题详情：求值：sin(－1200°)·cos1290°＋cos(－1020°)·sin(－1050°)＋tan945°．【回答】解：原式＝－sin1200°·cos1290°＋cos1020°·(－sin1050°)＋tan945°＝－sin120°·cos210°＋cos300°·(－sin330°)＋tan225°＝(－sin60°)·(－cos30°)＋cos6...