Could you please help me with proving these problems, i just dont get these ones

1.) cot^2x=(cscx-1)(cscx+1)

2.) tan^2x=sec^2x-sin^2x-cos^2x

3.) csc^3xtan^2x=cscx(1+tan^2x)

4.) sinx/1-cosx + sinx/1+cosx = 2cscx

5.) sinx/cscx-1 + sinx/cscx+1 = 2tan^2x

Please help, all is appreciated.