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1.求下列三角函数值的符号(1)tan(-23π/4)(2)cos(-59π/17)2.确定下列式子的符号(1)tan125°*sin273° (2)tan108°/cos305°(3)sin5/4*cos4/5*tan11π/6 (4)(cos5π/6*tan11π/6)/sin2/3π
题目详情
1.求下列三角函数值的符号(1)tan(-23π/4)(2)cos(-59π/17)
2.确定下列式子的符号(1)tan125°*sin273° (2)tan108°/cos305°
(3)sin5/4*cos4/5*tan11π/6 (4)(cos5π/6*tan11π/6)/sin2/3π
2.确定下列式子的符号(1)tan125°*sin273° (2)tan108°/cos305°
(3)sin5/4*cos4/5*tan11π/6 (4)(cos5π/6*tan11π/6)/sin2/3π
▼优质解答
答案和解析
I 全正
II正弦
III正、余切
IV 余弦
(1) 23/4=6-π/4
sin(-6π+π/4)
=sin(π/4)
第I象限,正弦>0
(2) sin(-59π/17)
=sin(-4π+9π/17)
=sin(9π/17),第三象限,
II正弦
III正、余切
IV 余弦
(1) 23/4=6-π/4
sin(-6π+π/4)
=sin(π/4)
第I象限,正弦>0
(2) sin(-59π/17)
=sin(-4π+9π/17)
=sin(9π/17),第三象限,
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