判断题-|||-tan (2pi +alpha )=tan alpha .-|||-39.-|||-A 对-|||-B 错

例1(1)(2021·全国甲卷)若 alpha in (0,dfrac (pi )(2)), tan2α-|||-=dfrac (cos alpha )(2-s

cos (3pi +alpha )=cos alpha -|||-A 对-|||-B 错

[问答题] 已知，求tan（α-2β）的值。

判断题：tan x)=(sec )^2xtan x)=(sec )^2x 正确 tan x)=(sec )^2x 错误判断题：正确错误

7.[福建2020适应性模拟]已知 tan alpha =2 ,则-|||-dfrac ({sin )^2alpha -(cos )^2alpha +2}(2{

[问答题] 已知，，（1）求tan2α的值：（2）求β。

3.判断题alpha_(1)=}125的列分块形式，对吗？A 对B 错3.判断题$\alpha_{1}=\begin{bmatrix}1\\2\\5\end{b

4.已知 sin alpha =-dfrac (3)(5), 且α是第三象限的角,则 cos alpha = __ ,-|||-tan alpha = __ o

4.(判断题) 向量组满足 beta_(1)=alpha_(1), beta_(2)=alpha_(1)+alpha_(2), beta_(3)=alpha_(

4.判断题向量β被向量组alpha_(1),alpha_(2),...,alpha_(n)线性表示，记A=[alpha_(1),alpha_(2),...,al