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`tan^(-1)""[(a cos x -b sinx)/(b cosx+a sinx)]` को सरल कीजिए, यदि `""(a)/(b)tanx le-1` |
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Answer» We have, LHS `=tan^(-1)(acosx-bsinx)/(bcosx-asinx)=tan^(-1){((acosx-bsinx)/(bcosx))/((bcosx-asinx)/(bcosx))` [on dividing num. and denom. By `bcosx`]. `=tan^(-1){(a/b-tanx)/(1+a/btanx)}=tan^(-1)(p-q)/(1+pq)`, where `a/b=p` and `tanx=q` `=tan^(-1)p-tan^(-1)q=tan^(-1)a/b-tan^(-1)(tanx)` `=(tan^(-1)a/b-x)`= RHS. Hence, `tan^(-1)((acosx-bsinx)/(bcosx-asinx))=(tan^(-1)a/b-x)`. |
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