Page 35 - Bangladesh_classwiz_BOOK2018_rev_Neat

g~j, Pig gvb Ges ZvwjKv gvb Rvbv _vK‡j wØNvZ dvsk‡bi ‡jLwPÎ AsKb Kiv mnR n‡q hvq|

Dc‡ii eY©bv¸‡jv ‡jLwP‡Î `…k¨gvb, ‡hwU ‡`Lv‡”Q ‡h, me©wbgœ gvb (1, −2) we›`yMvgx cive…ËwUi GKwU cÖwZmvg¨
‡iLv i‡q‡Q| hv A‡¶i mgvšÍivj Ges hvi mgxKiY = 1|

2.5 wÎNvZ dvskb

wÎNvZ dvsk‡b Pj‡Ki m‡e©v”P NvZ wZb n‡q _v‡K| ‰iwLK Ges wØNvZ dvsk‡bi g‡Zv ZvwjKv c×wZ wbw`©ó wÎNvZ
dvsk‡bi ‰ewkó¨ ‡evSvi Rb¨ mnvqK| D`vniY wn‡m‡e wb‡Pi ZvwjKv n‡Z ‡`Lv hv‡”Q ‡h, wÎNvZ dvskb ( ) =
3
e…w× cv‡”Q, hw`I Zv ‰iwLKfv‡e bq Ges Gi gvb < 0 Gi Rb¨ FYvZœK Ges > 0 Gi Rb¨ abvZœK|

‡hLv‡b GB wÎNvZ dvskb g~jwe›`y = 0 Gi mv‡c‡¶ cÖwZmg, wKš‘ Ab¨vb¨ wÎNvZ dvsk‡bi Zv bq| cybivq,
gv‡bi GKwU ZvwjKv dvsk‡bi ‡jLwP‡Îi AvK…wZ m¤ú‡K© AšÍt`…wó cÖ`vb K‡i wb‡Pi ‡Uwe‡j wfbœ GKwU wÎNvZ dvskb
( ) = ³ − − 1 ‡`Lv‡bv n‡q‡Q, hv g~j we›`yi mv‡c‡¶ cÖwZmvg¨ bq|

GB `yBwU ZvwjKv D³ `yBwU wÎNvZ dvsk‡bi ‡jLwPÎ m¤ú‡K© Kíbv Ki‡Z mvnvh¨ K‡i hv wb‡P QR ‡Kv‡Wi gva¨‡g
3
3
AwR©Z ‡jLwP‡Î ‡`Lv‡bv n‡q‡Q ‡hLv‡b ( ) = − − 1 I ( ) = | ‡jLwPÎwU GwU ¯úó K‡i ‡h,
wÎNvZ dvsk‡bi wewfbœ iKg AvK…wZ i‡q‡Q (hv ‰iwLK dvskb ‡hwUi AvK…wZ ïaygvÎ ‰iwLK Ges wØNvZ dvskb ‡hwUi
AvK…wZ ïaygvÎ cive…ËvKvi, Gi g‡Zv bq)|

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