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高一数学(1/sin10)-(√3sin80)的值是?
题目详情
高一数学(1/sin10)-(√3sin80)的值是?
▼优质解答
答案和解析
原式
=1/sin10-√3/cos10
=(cos10-√3sin10)/(sin10cos10)
=2*(1/2cos10-√3/2sin10)/(sin10cos10)
=2*(sin30cos10-cos30sin10)/(sin10cos10)
=4(sin(30-10))/(2sin10cos10)
=4(sin20)/sin20
=4
=1/sin10-√3/cos10
=(cos10-√3sin10)/(sin10cos10)
=2*(1/2cos10-√3/2sin10)/(sin10cos10)
=2*(sin30cos10-cos30sin10)/(sin10cos10)
=4(sin(30-10))/(2sin10cos10)
=4(sin20)/sin20
=4
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