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सिद्ध कीजिए कि `(cos(90^(@)+theta)sec(270^(@)+theta)sin(180^(@)+theta))/("cosec "(-theta)cos(270^(@)-theta)tan(180^(@)+theta))=cos theta` |
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Answer» बायाँ पक्ष `=(cos(90^(@)+theta)sec(270^(@)+theta)sin(180^(@)+theta))/("cosec "(-theta)cos(270^(@)-theta)tan(180^(@)+theta))=cos theta` `=(cos(90^(@)+theta)sec{180^(@)+(90^(@)+theta)}sin(180^(@)+theta))/(-"cosec "theta cos {180^(@)+(90^(@)-theta)}tan(180^(@)+theta))` `=(cos(90^(@)+theta){-sec(90^(@)+theta)}-{-sin theta})/(-"cosec "theta{-cos(90^(@)-theta)}tan theta)` `" "sin (180^(@)+theta )=-sin theta` `" " cos(180^(@)+theta)=-cos theta` `tan(180^(@)+theta)=tan theta` `" व "sec(180^(@)+theta)=-sec theta" का प्रयोग करते हुए")` `=((-sin theta)"cosec "theta(-sin theta))/((-"cosec "theta)(-sin theta)tan theta)" "cos (90^(@)+theta)=-sin theta` `" "sec(90^(@)+theta)= -"cosec "theta` `" "cos(90^(@)-theta)=sin theta` का प्रयोग करते हुए `=cos theta = ` दायाँ पक्ष |
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