1.[1/(cos80°)^2-3/(cos10°)^2].1/cos20°
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1.[1/(cos80°)^2-3/(cos10°)^2].1/cos20°
[1/(cos80°)^2-3/(cos10°)^2]
*[1/cos20]
=[(1/cos80 + √3/cos10) * (1/cos80 - √3/cos10)] *[1/cos20]
=[(1/sin10 + √3/cos10) * (1/sin10 - √3/cos10)] *[1/cos20]
=[(cos10+√3sin10)/sin10cos10 * (cos10-√3sin10)/sin10cos10] *[1/cos20]
=[4sin40/sin20 * 4cos70/sin20] *[1/cos20]
=[16sin40/sin20] *[1/cos20]
=[32cos20] *[1/cos20]
=32
*[1/cos20]
=[(1/cos80 + √3/cos10) * (1/cos80 - √3/cos10)] *[1/cos20]
=[(1/sin10 + √3/cos10) * (1/sin10 - √3/cos10)] *[1/cos20]
=[(cos10+√3sin10)/sin10cos10 * (cos10-√3sin10)/sin10cos10] *[1/cos20]
=[4sin40/sin20 * 4cos70/sin20] *[1/cos20]
=[16sin40/sin20] *[1/cos20]
=[32cos20] *[1/cos20]
=32
化简:sin50º(1+√3tan10°)-cos20°/cos80°√(1-cos20°)
求cos20°cos10
化简(tan10°-根号3)*(cos10°/sin50°)*(2cos10°-sin20°/cos20°)
求值:[sin50°(1+tan10°√3)-cos20°]/[cos80°乘以根号下1-cos20°]
求值:【sin50°[1+根号(3)tan10°]—cos20°】/[cos80°根号(1—cos20°)】
化简:【sin50°·(1+√3tan10° )-cos20°】/(cos80°· √1-cos20°)
化简sin50°(1+√3tan10°)-cos20°/cos80°√(1-cos20°)
1.(1—cos20° )除以(cos80° 乘sin20° )=根号二
1/2*cos10*sin10*cos20*cos40/cos10到1/4*sin20*cos20*cos40/cos1
化简:(cos10°+根号下3sin10°)/根号下(1-cos80°)=
1.cos20°cos40°cos80°的值为?
计算cos20°cos40°cos80°