【单选题】建筑砂浆的立方体的试件以3个为一组进行评定,当三个测值的最大值或最小值有一个与中间值的差值超过中间值的15%时,应取( )为抗压强度值。
【单选题】已知cos( π 4 +θ )?cos( π 4 -θ )= 3 4 ,θ∈( 3π 4 ,π),则sinθ+cosθ的值是( )
【单选题】已知α+β= π 3 ,则cosαcosβ- 3 sinαcosβ- 3 cosαsinβ-sinαsinβ 的值为( )
【单选题】2- sin 2 2+cos4 的值等于( )
【单选题】砂浆收缩试验应取三个试件测值的算术平均值作为干燥收缩值,当一个值与平均值偏差大于()时应剔除,当两个值超过()该组试件结果无效
【简答题】计算: - 2 2 +( 1 3 ) -1 -2cos60°+|-3| .
【简答题】计算: 2 2 +1 -(3.14-π ) 0 -3cos45°+( 2 2 ) -1 .
【简答题】化简:cos 2 1°+cos 2 2°+cos 2 3°+…+cos 2 89°.
【单选题】当 α= 3π 4 时,sin(α+β)+cos(α+β)+sin(α-β)+cos(α-β)=( )
【简答题】Look and choose.(看图,选择与图意相符的句子) ( )1. A. They’re climbing. B. They’re sleeping. C. They’re fighting. ( ) 2. A. They are swimming. B. They are drinking. C. They are jumping. ( ) 3. A. The t...