Yesterday I take a homework intererst in wien bridge oscillator circiut

We need a signal shown in figure.I need lt spice code in shown wıen bridge oscillator

 

Fix the other image.

 

If that wave is the output from a Wien Oscillator, it has horrible 5th harmonic distortion....

 

we find frequency with this wave. 50 Hz

 

Are you trying to simulate a voltage source which has the waveform shown? If so, consider using a 'behavioral voltage source', and read up about the Fourier components of a square wave.