1.C
2.C
3.A
4.A
5.A
6.C
7.B
8.A
9.B
10.C
11. $\frac{sin^2\alpha-cos^2\alpha+cos^2\alpha}{sin\alpha}-cos\alpha\cdot \frac{sin\alpha}{cos\alpha}=sin\alpha-sin\alpha=0.$ ■
12. $P(A)=\frac{16 \cdot 15}{25 \cdot 24}=\frac{2}{5}$
1.C
2.C
3.A
4.A
5.A
6.C
7.B
8.A
9.B
10.C
11. $\frac{sin^2\alpha-cos^2\alpha+cos^2\alpha}{sin\alpha}-cos\alpha\cdot \frac{sin\alpha}{cos\alpha}=sin\alpha-sin\alpha=0.$ ■
12. $P(A)=\frac{16 \cdot 15}{25 \cdot 24}=\frac{2}{5}$