Hi Shivendra,
Please check Example 26 of Chapter 3 Class 11 here https://www.teachoo.com/2230/586/Example-26---Prove-cos-2x-cos-x-2---cos-3x-cos-9x-2-=-sin-5x/category/Examples/
Written on March 25, 2017, 12:42 p.m.
Hi Shivendra,
Please check Example 26 of Chapter 3 Class 11 here https://www.teachoo.com/2230/586/Example-26---Prove-cos-2x-cos-x-2---cos-3x-cos-9x-2-=-sin-5x/category/Examples/
Written on March 25, 2017, 12:42 p.m.