Instead of a PDF, buy a used physical copy from OLX, Campus Book Fairs, or Amazon Renewed for as low as ₹200. You can then scan the chapters you need if you absolutely require a digital version.
Most engineering colleges subscribe to digital libraries like NPTEL or S. Chand Digital Hub.
S. Chand has officially digitized this book. You can purchase the e-book on Google Play for approximately ₹350 - ₹450.