class 9th math all theoram

In the given figure a diameter AB of circle bisects a chord CD if AD is parallel to BC. Prove that chord CD is also a diameter of circle  

Plz.. explain 

how to create on pass port service , visa , tour packages, bills generated on tally. 

How to find integration of cos2x/cosx

NO. 29 plz solve

Plz explain this concept ..

Sir, can you told how to create item list in tally and how to create invoice with gst

Thank you

x sin³  theta + y cos³  theta=sin thta cos theta,

x sin theta - y cos theta =0

find the value of x² + y²