Question

要求不用计算器求解cos(5π/6)-cot37°×cot137°×tan225°=______.

Answer 1

cos(5π/6)= - cos(π/6)= - √3/2cot127°= cot(90°+37°) = - tan37° 【cot(π/2+α)=-tan α 】 ∴cot37°×cot137°=cot37°x( - tan37°) = -1 【cotα=1/tan α 】tan225°=tan45°=1 【tan（π+α）=tan α...