L.H.S=Tan@+sec@-1/tan@-sec@+1 =(tan@+sec@)-(sec^2@-tan^2@)/tan@-sec@+1 =(sec@+tan@)-{(sec@+tan@)(sec@-tan@)}/tan@-sec@+1 =(sec@+tan@){1-(sec@-tan@)}/tan@-sec@+1[এখানে sec@+tan@ কমন নেওয়া হলো]] =(sec@+tan@)(1-sec@+tan@)/tan@-sec@+1 =(sec@+tan@)(tan@-sec@+1)/tan@-sec@+1 =sec@+tan@ =R.H.S L.H.S=R.H.S(PROVED) বোঝতে সমস্যা হলে comment koro