how can you prove this ..

1. sin² [theta] + cos² [theta]/cos² [theta] = |1/cos [theta]|²

2. 1-cos²[theta]/sin [theta] = sin [theta]_

3. 1+cot²[theta]/csc ²[theta]=1

4. csc² [theta]-1/csc²[theta]=cos²[theta]

5. cot [theta] 1 =csc [theta] sec [theta]/ sec [theta]

6. cos [theta] / sec [theta] + tan [theta] = 1-sin [theta]

7. csc²[theta] = _cos ² [theta] + cot² [theta] + sin² [theta]

8. 2 cos² [theta]-1 =cos (4th power) [theta] sin (4th power) [theta]

9. cos [theta]/1+sin [theta] + cos [theta] /1-sin [theta] = 2/ cos theta

10. sin (4th power) [theta]-1/cos ² [theta]=cos² [theta] -2