Page 109 - Bangladesh_classwiz_BOOK2018_rev_Neat

5
2. + = n‡j, − tan Gi gvb wbY©q Ki‡Z n‡e|
2
mgvavb- G Rb¨ cÖ_‡g Qr (=) e¨envi K‡i cÖ_g mgxKiYwU wb‡Pi cÖ_g w¯Œ‡bi g‡Zv K‡i cÖ‡ek Kwi‡q

qr Pvc‡j 1g w¯Œ‡bi g‡Zv Gi gvb PvB‡e| Gi cÖvß gvb 46.39718103| Jz (A) †P‡c
1
GB gvbwU ‡g‡gvix‡Z msiÿY K‡i Z…Zxq w¯Œ‡bi g‡Zv − tan( ) K¨jKz‡jU‡i UvBc K‡i = Pvc‡j
cos ( )
2
djvdj ⁄ cvIqv hv‡e|
5

(Key log- 1akQz)$+lQz)Qr5a2qr
30==Jz1akQz)$plQz)=)

1 1
3. + Gi gvb wbY©q Ki‡Z n‡e|
2
2
1+sin 1+cosec
mgvavb- cÖ_‡g †g‡gvwi‡Z J e¨envi K‡i 45 msiÿY Ki‡Z n‡e| Gici wb‡Pi 2q w¯Œ‡bi g‡Zv K‡i
2
2
2
ivwkwUi UvBc Ki‡Z n‡e| GLv‡b sin = (sin ) Ges = 1 wjLv n‡q‡Q| Gici =
(sin ) 2
evUb Pvc‡j djvdj cvIqv hv‡e| G‡ÿ‡Î djvdj 1.

(Key log- 45Jz1a1+(jQz))d$+1a1

+1a(jQz))d=)

2
4. 1−cot 60° Gi gvb wbYq Ki‡Z n‡e|
©
2
1+cot 60°
mgvavb- GRb¨ cÖ_‡g wb‡Pi cÖ_g w¯Œ‡bi g‡Zv K‡i gvbwU cÖ‡ek Kwi‡q = evUb Pvc‡j mivmwi djvdj cÖ`wk©Z
n‡e|

(Key log- a1p1al60x)d$$1+1al60
x)d=)

2
G‡ÿ‡Î 60 Gi cwie‡Z© 1 wjLv n‡q‡Q †Kbbv cot = 1 .
( 60°) 2 tan

104