计算﹙sin3π/8﹚/﹙cos3π/8﹚-tanπ/8的结果为
问题描述:
计算﹙sin3π/8﹚/﹙cos3π/8﹚-tanπ/8的结果为
答
﹙sin3π/8﹚/﹙cos3π/8﹚-tanπ/8=sin(π/2-π/8 )/cos(π/2 -π/8 )-tanπ/8 =[(cosπ/8) /(sinπ/8) ]-[(sinπ/8) /(cosπ/8)]=[cos^2π/8 -sin^2π/8 ]/[sinπ/8 *cosπ/8 ]=2[cosπ/4 ]/[s...