✨ Best Answer ✨
実際に何項か書いてみると分かると思います。
(b2-b1)+(b3-b2)+…+(bn-b(n-1))+(b(n+1)-bn)
=-b1+b(n+1)=b(n+1)-b1
このように、バシバシ消えていきますよ！
Answers
Were you able to resolve your confusion?
Users viewing this question
are also looking at these questions 😉
✨ Best Answer ✨
実際に何項か書いてみると分かると思います。
(b2-b1)+(b3-b2)+…+(bn-b(n-1))+(b(n+1)-bn)
=-b1+b(n+1)=b(n+1)-b1
このように、バシバシ消えていきますよ！
Users viewing this question
are also looking at these questions 😉
![⑶で、第15項と第40項を求めて[1]の公式を使うのはできませんか？
2枚目どこまちがって... - 1](https://d1e9oo257tadp1.cloudfront.net/uploads/qa_question_image/file/1807803/thumb_l_webp_17829043939990.webp?Expires=1783321790&Signature=N3umkUHiVLTlz5ADfcCNh9LYI9QHfsQwnq2OqzyHIKrB7wV-NknhaA3mxSOojBem3u1e~BY9KT1~gW~mRuFq4w0voG-pj9w0kIEm9yJpsShLZFIJdhqX1aV1lmdZR6kirR18AjAtDj3zxexWFXi5gUda-FNrIjnZ3cq5hbmWISfTyY3rZlAufX8TTGEY4V7JgrFfescSJkg-zYvsMjN9lQqo0qIA23dzVec5v2byPbJRV63M8hm33u0koGfugz69AbBFFwtlyG~Qimy0R-yyonxawj3bInlpVTTmjfMcyQQBfyZXyLl1xP0KPJ7cHyeYQ0pHeo1Z3Bo1d5~ee4QVdw__&Key-Pair-Id=K2W722D70GJS8W&Expires=1783321790&Signature=EOkG7reYILQW723kqU17~oa3zApcYFaxpYDDObQ1FoqOCguUTxRBbAuwNlbO8xNikjyS9saUn6M4uetpURxq56ovl-9n2GfQI2InL83IWfqAI4HDqGJKYwxVaBevQbGIAAnxzuO2Nq~hnBcOs2gYTntCM8NRL4mL1ZJwNb0440twupWw14xbF6jj6YW0c10t7nf3JOo6j54ZBIoLWQjCLSdzvJqD4QtGWDjDydCEBfVJgqDXS91TyLP6TapyTbff9OZCWSFxmI1JQJecwmqN-vlwV2o7uy5jTmcsPgbOF1bZbrrsAvspRULYaVT05Ha1GSb-vAa2dxFh0Is82lBm4g__&Key-Pair-Id=K2W722D70GJS8W)
![⑶で、第15項と第40項を求めて[1]の公式を使うのはできませんか？
2枚目どこまちがって... - 2](https://d1e9oo257tadp1.cloudfront.net/uploads/qa_question_image/file/1807804/thumb_l_webp_17829043940640.webp?Expires=1783321790&Signature=kw3tSzU50MMXlVuiZGSlspXDFQcBcEGAKljytv~FrF02fPKKUxziFHDzOPdUT5K1cbOcigOfEnOmPp1Z1CIZInbPk4x~-gycvAiHQnJrTiGM~E2W-J5hy8I2mgH0QeOa22SOtWKuZNywJKlHXAfc3DpXRVynyDGu-XpXKKlL8rHXiS~sKccZfzYNtPx1ft~6vSjrBgnVYWXgk7NmRkY0enyTyuvwoUZDysoG5pILn4kSwWZLSuPVenz4ZWpH4JhcpnQ90gRwWYPwFwtOkn4IzvnQJi9JuZXbQAMNuZMwdbpNDeKudAnL8a2~FD5zQBWq90OR7kKpCNEVHkBZ0zQSlw__&Key-Pair-Id=K2W722D70GJS8W&Expires=1783321790&Signature=OcMKFRAQZjMD6ohd~lcL-Tpa8tzWLQH4Zg-kGF4aWmzUDJs~KTq~CCWNEMi4QpsqCoZTJoVm0dPyQgi1FEDi~5FPlaIhs65SVgvl1i6AT-ASLiZssElY~SC2SODSalgxEa-xlzZwqwDxxep6BqHo5S~8GWwH0Itw9ZxmErDSFSwHqfuPsIS6a4KMf2aVOecT6WfjdtCZfJCVttnZUiJS7SeMascO9Mk6L9ZfIjpH88Emn6ke3iRaBzbIicvzxbXEYdZrnoCANE93dx0MJSxo3usRwE52fw2KlSHdK2WEaKcmcoDFxAcFi7t2nhbRozSeOSLp-XBu5S-kUIauRVaoow__&Key-Pair-Id=K2W722D70GJS8W)
なるほど！