Question

计算:

(1)sin390°+cos(-660°)+3tan405°-sec540°;

(2)sin(-)+tanπ-2cos0+cot-csc.

Answer 1

解析:(1)原式=sin(360°+30°)+cos(-2×360°+60°)+3tan(360°+45°)-sec(360°+180°)

=sin30°+cos60°+3tan45°-sec180°

=++3×1-(-1)=5.

(2)原式=sin(-4π+)+tanπ-2cos0+cot(2π+)-csc(2π+)

=sin+tanπ-2cos0+cot-csc

=1+0-2+1-=-.