Question

求下列各三角函数值

1、sin750° 2、cos 22π/3 3、tan(-7π/4) 4、sin900°
要过程

Answer 1

解：1、sin750°
=sin(360×2+30)°
=sin30°
=0.5

2、cos 22π/3
=cos(6π+4π/3)
=cos 4π/3
=-0.5

3、tan(-7π/4)
=tan(-2π+π/4)
=tan π/4
=1

4、sin900°
=sin(360×2+180)°
=sin180°
=0

望采纳，谢谢！

追问

第一题不应该是﹙30°+2×360°﹚吗

追答

(360×2+30)°就是30°+2×360°，只不过单位“°”被提取出括号外了，实质是一样的

Answer 2

1、sin750° =sin（720°+30°）=sin30° =0.5
2、cos 22π/3=cos（ 6π+4π/3）=cos4π/3=-0.5
3、tan(-7π/4)=tan(-π-3π/4)=tan(-3π/4)=-tan3π/4=1
4、sin900°=sin（720+180）°=sin180°=0

Answer 3

sin750度＝sin30度＝1/2.
　
cos22派/3=cos2派/3=--cos派/3=--1/2.

tan(--7派/4)=tan(派/4)=1.

sin900度＝sin180度＝0.

Answer 4

1 =sin(π/6)=1/2

2 =cos(π+π/3)= -cos(π/3)= -1/2
3 = -tan(π+3π/4)= -tan(3π/4)=tan(π/4)=1
4 =sin(5π)=sin(π)=0