InterviewSolution
Saved Bookmarks
| 1. |
किसी `Delta ABC` में सिद्ध कीजिए कि- `asin((B-C)/(2))=(b-c)cos.(A)/(2)` |
|
Answer» sine सूत्र से , `(sinA)/(a)=(sinB)/(b)=(sinC)/(c)=(1)/(k)` (माना) `a=k sin A` `b=k sinB` `c=k sin C` इसलिए `(b-c)/(a)=(k sin B-ksinC)/(k sin A)` `=(sinB-sinC)/(sinA)` `=(2cos ((B+C)/(2))sin((B-C)/(2)))/(2sin.(A)/(2)cos.(A)/(2))=(cos((pi)/(2)-(A)/(2))sin((B-C)/(2)))/(sin.(A)/(2)cos.(A)/(2))` `=(sin.(A)/(2)sin((B-C)/(2)))/(sin.(A)/(2)cos.(A)/(2))=sin((B-C)/(2))/(cos.(A)/(2))` इसलिए `a sin((B-C)/(2))=(b-c)cos.(A)/(2)`. |
|