高一数学三角函数题，在线等！

显示全部楼层 · 2012-3-3 18:47:18

（1）sin(-π/4)=- sin(π/4)=-√2/2.（2）cos(-60°)= cos(60°)=1/2.（3）tan(-9π/4)= tan(-2π-π/4)= tan(-π/4)=- tan(π/4)=-1.（4）sin(-390°)= sin(-360°-30°)= sin(-30°)=- sin(30°)=-1/2....

千问 · 2012-3-3 18:47:18

（1）：-sin(π/4)=-√2/2(2):cos(60°)=1/2(3):tan(π/4)=1(4):sin(30°)=1/2...

千问 · 2012-3-3 18:47:18

(1)Sin(-π/4)=-Sinπ/4=-√2/2(2)Cos(-60)=Cos60=1/2(3)tan(-9π/4)=tan(-2π-π/4)=-tanπ/4=-1(4)Sin(-390)=Sin(-360-30)=-Sin30=-1/2...

千问 · 2012-3-3 18:47:18

sin(-π/4)=-sin(π/4)=√2/2cos(-60°)=cos(60°)=1/2tan(-9π/4)=-tan(π/4)=1sin(-390°)=-sin(30°)=1/2...

千问 · 2012-3-3 18:47:18

sin(-π/4)=sin(π/4)=√2／2...