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- e 1. Prove that : <059 -sin6+1= cosecÂŽ + cotÂŽcosO+sinB -1[Sample Question Paper 2017 |
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Answer» CosA-sinA+1/cosA+sinA-1=(cosA-sinA+1)(cosA+sinA+1)/(cosA+sinA-1)(cosA+sinA+1)=(cos²A-cosAsinA+cosA+cosAsinA-sin²A+sinA+cosA-sinA+1)/{(cosA+sinA)²-(1)²}=(cos²A-sin²A+2cosA+1)/(cos²A+2cosAsinA+sin²A-1)={cos²A+2cosA+(1-sin²A)}/(1+2cosAsinA-1) [∵, sin²A+cos²A=1]=(cos²A+2cosA+cos²A)/2cosAsinA=(2cos²A+2cosA)/2cosAsinA=2cosA(cosA+1)/2cosAsinA=(cosA+1)/sinA=cosA/sinA+1/sinA=cotA+cosecA=cosecA+cotA (Proved) long method |
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