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1. $2 \sin 30° + 3 \cos 60° - 4 \tan 45°$.
答案：
1. 解:原式$=2 × \frac{1}{2}+3 × \frac{1}{2}-4 × 1=1+\frac{3}{2}-4=-\frac{3}{2}$.
2. $\cos^2 60° - \frac{\cos 60°}{1 - \sin 30°} + \tan^2 45° - \sin^2 45°$.
答案：
解:原式$=(\frac{1}{2})^{2}-\frac{\frac{1}{2}}{1 - \frac{1}{2}} + 1^{2}-(\frac{\sqrt{2}}{2})^{2}$
$=\frac{1}{4}-\frac{\frac{1}{2}}{\frac{1}{2}} + 1 - \frac{1}{2}$
$=\frac{1}{4}-1 + 1 - \frac{1}{2}$
$=-\frac{1}{4}$
3. $|\tan 30° - 1| + 2 \sin 60° - \tan 45°$.
答案：
3. 解:原式$= |\frac{\sqrt{3}}{3}-1|-2 × \frac{\sqrt{3}}{2}-1=1-\frac{\sqrt{3}}{3}+\sqrt{3}-1=\frac{2\sqrt{3}}{3}$.
4. $\sin 30° - \frac{\sqrt{2}}{2} \cos 45° + \frac{1}{3} \tan^2 60°$.
答案：
4. 解:原式$=\frac{1}{2}-\frac{\sqrt{2}}{2} × \frac{\sqrt{2}}{2}+\frac{1}{3} × (\sqrt{3})^{2}=\frac{1}{2}-\frac{1}{2}+\frac{1}{3} ×3=1$.
5. $\frac{\sin 45°}{\cos 30° - \tan 60°} + \cos 45° · \tan 60°$.
答案：
5. 解:原式$=\frac{\frac{\sqrt{2}}{2}}{\frac{\sqrt{3}}{2}-\sqrt{3}}+\frac{\sqrt{2}}{2} × \sqrt{3}=\frac{\frac{\sqrt{2}}{2}}{-\frac{\sqrt{3}}{2}}+\frac{\sqrt{6}}{2}=-\frac{\sqrt{6}}{3}+\frac{\sqrt{6}}{2}=\frac{\sqrt{6}}{6}$.
6. $2 \sin 30° - 3 \tan 45° · \sin 45° + 4 \cos 60°$.
答案：
6. 解:原式$=2 × \frac{1}{2}-3 × 1 × \frac{\sqrt{2}}{2}+4 × \frac{1}{2}=1-\frac{3\sqrt{2}}{2}+2=3-\frac{3\sqrt{2}}{2}$.
7. $\frac{\cos^2 30°}{1 + \sin 30°} + \tan^2 60°$.
答案：
解：原式$=\frac{(\frac{\sqrt{3}}{2})^{2}}{1+\frac{1}{2}}+(\sqrt{3})^{2}=\frac{\frac{3}{4}}{\frac{3}{2}}+3=\frac{7}{2}$.
8. $2 \cos 45° - \frac{3}{2} \tan 30° · \cos 30° + \sin^2 60°$.
答案：
8. 解:原式$=2 × \frac{\sqrt{2}}{2}-\frac{3}{2} × \frac{\sqrt{3}}{3} × \frac{\sqrt{3}}{2}+(\frac{\sqrt{3}}{2})^{2}=\sqrt{2}-\frac{3}{4}+\frac{3}{4}=\sqrt{2}$.
9. $\sin^2 30° + \sin 60° - \sin^2 45° + \cos^2 30°$.
答案：
9. 解:原式$=(\frac{1}{2})^{2}+\frac{\sqrt{3}}{2}-(\frac{\sqrt{2}}{2})^{2}+(\frac{\sqrt{3}}{2})^{2}=\frac{1}{4}+\frac{\sqrt{3}}{2}-\frac{1}{2}+\frac{3}{4}=\frac{1+\sqrt{3}}{2}$.
10. $3 \tan 30° - \frac{1}{\cos 60°} + \sqrt{8} \cos 45° + \sqrt{(1 - \tan 60°)^2}$.
答案：
10. 解:原式$=3 × \frac{\sqrt{3}}{3}-\frac{1}{\frac{1}{2}}+\sqrt{8} × \frac{\sqrt{2}}{2}+\sqrt{(1-\sqrt{3})^{2}}=\sqrt{3}-2+2+\sqrt{3}-1=2\sqrt{3}-1$.
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