00243nam a2200109 a 450000500170000008200200001710000170003724500170005425000120007126000390008330000110012220251203091756.0  a516.24,bD, Vit  aVittal, P.R.  aTrigonometry  a2nd Ed.  aMadrasbMargham Publicationsc1996  a22 cm.