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7.13. r(ϕ) =ϕ sin ϕ + cos ϕ; îá÷èñëèòè r′(π);<br />
7.14. z =(y 2 –2y) tgy; îá÷èñëèòè z′(0);<br />
2x<br />
7.32.<br />
−<br />
z = 3e x x ; 7.33. g=arctg<br />
2<br />
1 − x<br />
;<br />
7.15.<br />
2 2<br />
r 2x<br />
u()<br />
r = 2 2<br />
2x<br />
− r<br />
; îá÷èñëèòè<br />
⎛du<br />
⎞<br />
⎜ ⎟<br />
dr<br />
;<br />
⎝ ⎠ =<br />
r<br />
x<br />
7.34. y = arcsin x; 7.35. ω= ln(sin(cos7 t))<br />
.<br />
7.9. ÏÎÕ²ÄͲ ÂÈÙÈÕ ÏÎÐßÄʲÂ<br />
7.16. y = ( 2+ 3x) 5<br />
; 7.17. y sin( 2x<br />
1)<br />
= − ;<br />
7.18. y = ctg x ; 7.19. 3<br />
z = x + x ;<br />
7.20.<br />
v =<br />
1<br />
( 1+<br />
sin4y<br />
) 3<br />
; 7.21. y = x<br />
3 3 x ;<br />
sin x<br />
7.22. y = lncos3x; 7.23. y =<br />
2 ;<br />
2cos x<br />
7.24. y = sin 2 x + sin x 2 ; îá÷èñëèòè y′(0);<br />
x a<br />
7.25. y = cos cos<br />
a<br />
+ x<br />
; à — ñòàëà; îá÷èñëèòè y′(a);<br />
3<br />
e<br />
7.26. y = ln ; îá÷èñëèòè y′(0);<br />
1<br />
x3x<br />
+ e<br />
x 1 x<br />
7.27. fx ( ) = 3 + + 6<br />
5x<br />
; îá÷èñëèòè f′(1);<br />
2<br />
1+<br />
x<br />
2<br />
7.28. y = cos x− 2ln cos x; 7.29. v = ln 1 − x<br />
;<br />
aϕ<br />
= − ; 7.31. x( ϕ ) = e sint ϕ;<br />
7.30. z x( 1 lnx)<br />
7.9.1. Îçíà÷åííÿ<br />
ßêùî ó′ º ïîõ³äíà â³ä ôóíêö³¿ ó = f(õ) (çà óìîâè, ùî âîíà<br />
³ñíóº), òî ïîõ³äíà â³ä ó′ íàçèâàºòüñÿ äðóãîþ ïîõ³äíîþ, àáî<br />
ïîõ³äíîþ äðóãîãî ïîðÿäêó, â³ä ôóíêö³¿ ó ³ ïîçíà÷àºòüñÿ ó′′,<br />
2<br />
dy<br />
àáî f′′(õ), àáî 2<br />
dx .<br />
Àíàëîã³÷íî îçíà÷àþòüñÿ ³ ïîçíà÷àþòüñÿ ïîõ³äí³ áóäüÿêîãî<br />
ïîðÿäêó:<br />
dy<br />
ïîõ³äíà òðåòüîãî ïîðÿäêó (ó′′)′ = ó′′′(õ) = 3 3<br />
dx ;<br />
ïîõ³äíà ÷åòâåðòîãî ïîðÿäêó (ó′′′)′ = ó (4) = f (4) (õ) =<br />
4<br />
d y<br />
4<br />
dx ;<br />
dy<br />
ïîõ³äíà n-ãî ïîðÿäêó (y (n-1) )′ = y (n) = f (n) (x) =<br />
n n<br />
dx .<br />
Ó çàãàëüíîìó âèïàäêó äëÿ çíàõîäæåííÿ ïîõ³äíî¿ áóäüÿêîãî<br />
âèùîãî ïîðÿäêó â³ä äàíî¿ ôóíêö³¿ äîâîäèòüñÿ ïîñë³äîâíî<br />
çíàõîäèòè óñ³ ¿¿ ïîõ³äí³ íèæ÷èõ ïîðÿäê³â.<br />
7.9.2. Ïðèêëàäè<br />
Äëÿ äàíèõ ôóíêö³é çíàéòè ïîõ³äí³ âêàçàíîãî ïîðÿäêó (â<br />
äåÿêèõ âèïàäêàõ, êð³ì öüîãî, äîäàòêîâî òðåáà çíàéòè çíà-<br />
÷åííÿ â³äïîâ³äíî¿ ïîõ³äíî¿ ó çàäàí³é òî÷ö³):<br />
7.9.1. ó = õ 5 +7õ 3 + 9, ó (6) =?<br />
7.9.2. ó =lnõ, ó (5) = ? 7.9.3. y = x ln x, ó (6) =?<br />
7.9.4. s = arctg 2x, s′′(–1) = ? 7.9.5. y = x m , m∈N; y (k) =?<br />
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