f(x)=cosx/cos(π/6-x),则f(1°)+f(2°)+……+f(59°)
问题描述:
f(x)=cosx/cos(π/6-x),则f(1°)+f(2°)+……+f(59°)
答
因为cosx/cos(π/6-x)+cos(π/3-x)/cos[π/6-(π/3-x)]
=cosx/cos(π/6-x)+cos(π/3-x)/cos(π/6-x)
=√3cos(π/6-x)/cos(π/6-x)
=√3
所以f(1°)+f(2°)+……+f(59°)=[f(1°)+f(59°)]+[f(2°)+f(58°)]+……+[f(29°)+f(31°)]+f(30°)=29√3+√3/2=59√3/2