已知tan(π+α)=3 求2cos(π-α)-3sin(π+α)/4cos(-α)+sin(2π-α)的值_数学解答

已知tan(π+α)=3 求2cos(π-α)-3sin(π+α)/4cos(-α)+sin(2π-α)的值

人气：484 ℃　时间：2019-11-25 12:54:06

解答

tan(π+α)=3
tana=3
2cos(π-α)-3sin(π+α)/4cos(-α)+sin(2π-α)
=(-2cosa+3sinα)/(4cosα-sinα)
=(-2+3tanα)/(4-tanα)
=7