y 7 6 5 )4 (Cf 3 2 )(y=2 1 J→ →I-8 -7 -6 -5 -4 -3 -2 -1 0 12345678 x -1 -2 )(x=1 -3 -4 ﺍﻟﺘﻤﺭﻴﻥ :11 ﻟﺩﻴﻨﺎf (x ) = x3 + x 2 − 5x + 3 : 1ﺩﺭﺍﺴﺔ ﺘﻐﻴﺭﺍﺕ ﺍﻟﺩﺍﻟﺔfﺍﻟﺩﺍﻟﺔ ﺩﺍﻟﺔ ﻜﺜﻴﺭﺓ ﺍﻟﺤﺩﻭﺩ ﻤﻌﺭﻓﺔ ﻋﻠﻰ ℜﻭﻗﺎﺒﻠﺔ ﻟﻼﺸﺘﻘﺎﻕ ﻋﻠﻰ ℜ ﺇﺫﻥ [∞Df =]−∞,+ • ﺤﺴﺎﺏ ﺍﻟﻨﻬﺎﻴﺎﺕ : ∞lim x → f ( x ) = lim ( x 3 ) = − ∞− ∞ x → − ∞lim x → f ( x ) = lim ( x 3 ) = + ∞+ ∞ x → + •ﻋﺒﺎﺭﺓ ﺍﻟﺩﺍﻟﺔ ﺍﻟﻤﺸﺘﻘﺔ: ﻤﻥ ﺃﺠل xﻤﻥ Dfﻟﺩﻴﻨﺎ f '(x) = 3x 2 + 2x − 5 ﺇﺸﺎﺭﺓ )f '(x ﺤﺴﺎﺏ ﺍﻟﻤﻤﻴﺯ ∆ ﻟﺩﻴﻨﺎ ∆=b2-4ac=4-4(-5)(3)=64 ﻭﻤﻨﻪ ﺍﻟﻤﻌﺎﺩﻟﺔ f′(x)=0ﻟﻬﺎ ﺤﻼﻥ ﻤﺘﻤﺎﻴﺯﺍﻥ x2 = − 2+ 8 =1 ﻭ x1 = − 2− 8 = − 5 6 6 3 ﺇﺸﺎﺭﺓ ) f '(xﺘﻠﺨﺹ ﻓﻲ ﺍﻟﺠﺩﻭل ﺍﻟﺘﺎﻟﻲ∞x - − 5 1 ∞+ 3f′(x) + - +
ﺠﺩﻭل ﺍﻟﺘﻐﻴﺭﺍﺕ ∞x - 5 ∞+ −3 1 f′(x) + - + 34 ∞+ 3 )f(x -∞ 0 f (− 5 =) 34 ﻭ ﻟﺩﻴﻨﺎ f(1)=0 3 3 2ﺇﺤﺩﺍﺜﻴﺎ ﻨﻘﻁﺔ ﺍﻻﻨﻌﻁﺎﻑ ﻟﺩﻴﻨﺎ ﻤﻥ ﺍﺠل ﻜل xﻤﻥ f '(x) = 3x 2 + 2x − 5 Df ﻭﺍﻟﺩﺍﻟﺔ '' fﻗﺎﺒﻠﺔ ﻟﻼﺸﺘﻘﺎﻕ ﻋﻠﻰ Dfﺇﺫﻥ f ''( x)=6 x+ 2 ﺇﺸﺎﺭﺓ )f ''(x x = − 2 = − 1 6x+2=0ﻭﻤﻨﻪ f′′(x)=0ﻴﻜﺎﻓﺊ ﻟﺩﻴﻨﺎ 6 3 ∞x - 1 ∞− 3 +)f′′(x - + wﻨﻘﻁﺔ (− 1 , f (− 1 )) ﺍﻟﻨﻘﻁﺔ ﺇﺫﻥ ﺇﺸﺎﺭﺘﻬﺎ ﻭﺘﻐﻴﺭ x = − 1 ﺍﻟﺩﺍﻟﺔ '' fﺘﻨﻌﺩﻡ ﻤﻥ ﺍﺠل 3 3 3 ﺍﻨﻌﻁﺎﻑ ﻟﻤﻨﺤﻨﻰ ﺍﻟﺩﺍﻟﺔ f f (− 1 =) 128 ﻋﻠﻤﺎ ﺃﻥ 3 81 3ﻤﻌﺎﺩﻟﺔ ﺍﻟﻤﻤﺎﺱ)∆( ﻋﻨﺩ ﺍﻟﻨﻘﻁﺔ Aﺫﺍﺕ ﺍﻟﻔﺎﺼﻠﺔ -1 )y=f′(-1)(x+1)+f(-1 ﻭﻟﺩﻴﻨﺎ f′(-1)=-4 ، f(-1)=8 y=-4x+1)+8=-4x-4+8 ﺇﺫﻥ y= -4x+4 ﻭﻤﻨﻪ ﻤﻌﺎﺩﻟﺔ )∆( ﻫﻲ 4ﺇﻨﺸﺎﺀ ﺍﻟﻤﻨﺤﻨﻰ ) (Cﻭﺍﻟﻤﻤﺎﺱ)∆(
f(0)=3 , f (−13)=18218 , f(1)=0 y 11 10 9 8)∆( 7 )(Cf 6 5 4 3 2 1 →β J→ I-8 -7 -6 -5 -4 -3 -2 -1 0 12345678 x -1 5ﺤل ﺒﻴﺎﻨﻴﺎ ﺍﻟﻤﺘﺭﺍﺠﺤﺔ f (x) ≥ 0ﻨﻼﺤﻅ ﺃﻥ ) (Cfﻴﻘﻊ ﻓﻭﻕ ﺤﺎﻤل ﻤﺤﻭﺭ ﺍﻟﻔﻭﺍﺼل ﻤﻥ ﺍﺠل xﻤﻥ ﺍﻟﻤﺠﺎل [∞[ β , + ﺇﺫﻥ f (x) ≥ 0ﻴﻜﺎﻓﺊ ﺃﻥ [ ∞x ∈[ β , +ﺤﻴﺙ βﻫﻲ ﻓﺎﺼﻠﺔ ﻨﻘﻁﺔ ﺘﻘﺎﻁﻊ ) (Cfﻤﻊ ﺤﺎﻤل ﻤﺤﻭﺭ ﺍﻟﻔﻭﺍﺼل. f(x)=-x3+3x-2 ﺍﻟﺘﻤﺭﻴﻥ 12 ﻟﺩﻴﻨﺎ 1ﺩﺭﺍﺴﺔ ﺘﻐﻴﺭﺍﺕ ﺍﻟﺩﺍﻟﺔ f • ﻤﺠﻤﻭﻋﺔ ﺍﻟﺘﻌﺭﻴﻑ Df ﺍﻟﺩﺍﻟﺔ fﻫﻲ ﺩﺍﻟﺔ ﻜﺜﻴﺭ ﺤﺩﻭﺩ ،ﻓﻬﻲ ﻤﻌﺭﻓﺔ ﻋﻠﻰ IRﺇﺫﻥ [∞Df=]−∞ ,+ • ﺤﺴﺎﺏ ﺍﻟﻨﻬﺎﻴﺎﺕ ∞lim x a f ( x ) = lim ( − x 3 ) = + ∞−∞ −∞lim x a f ( x ) = lim ( − x 3 ) = −∞+∞ + •ﺍﻟﺩﺍﻟﺔ ﺍﻟﻤﺸﺘﻘﺔ ﺍﻟﺩﺍﻟﺔ fﺩﺍﻟﺔ ﻜﺜﻴﺭ ﺤﺩﻭﺩ ،ﻓﻬﻲ ﻗﺎﺒﻠﺔ ﻟﻼﺸﺘﻘﺎﻕ ﻋﻠﻰ ، IR ﻤﻥ ﺃﺠل ﻜل ﻋﺩﺩ xﻤﻥ IRﻟﺩﻴﻨﺎ f′(x) = -3x2+3 : ﻟﺩﻴﻨﺎ f′(x)=0 :ﻴﻜﺎﻓﺊ )(-3x2+3=0 -3x2=-3 ﻭﻤﻨﻪ ﺇﺫﻥ x2= 1ﺃﻱ ) (x= 1ﺃﻭ ) (x = -1
∞x - -1 1 ﺇﺸﺎﺭﺓ ) f′(xﺘﻠﺨﺹ ﻓﻲ ﺍﻟﺠﺩﻭل ﺍﻟﺘﺎﻟﻲ f′(x) - + ∞+∞x - -)f′(x∞f(x) + -1 1 •ﺠﺩﻭل ﺍﻟﺘﻐﻴﺭﺍﺕ -+ ∞+ - 0 ∞-4 - ﻭﻟﺩﻴﻨﺎ f(-1) = -(-1)3+3(-1)-2 = 1-3-2 = -4: f(1)=-(1)3+3(1)-2 = -1+3-2 = 0 2ﻨﺒﻴﻥ ﺃﻥ ) f(xﺘﻜﺘﺏ ﻋﻠﻰ ﺍﻟﺸﻜل )f(x) = (x-1)(-x2-x+2 )f(x) = (x-1)(-x2-x+2 ﻟﺩﻴﻨﺎ f(x)= -x3-x2+2x+x2+x-2 ﻭﻤﻨﻪ ﺒﺎﻟﻨﺸﺭ ﻨﺠﺫ : f(x) = -x3+3x-2 ﺇﺫﻥ : ﻭﻫﻭ ﺍﻟﻤﻁﻠﻭﺏ • ﺤل ﺍﻟﻤﻌﺎﺩﻟﺔ f(x) = 0 ﻟﺩﻴﻨﺎ f(x)= 0ﺘﻜﺎﻓﺊ (x-1) (-x2-x+2)=0 ) (x-1=0ﺃﻭ )(-x2-x+2=0 ﻭﻤﻨﻪ : )(-x2-x+2=0 ) (x= 1ﺃﻭ ﺃﻱ ﺃﻥ : ﺤل ﺍﻟﻤﻌﺎﺩﻟﺔ )*(…-x2-x+2=0 ﺤﺴﺎﺏ ﺍﻟﻤﻤﻴﺯ ∆ ﻟﺩﻴﻨﺎ ∆=b2-4ac=(-1)2-4(-1)(2)= 1+8 = 9 ﻭﻤﻨﻪ ﺍﻟﻤﻌﺎﺩﻟﺔ )*(ﺘﻘﺒل ﺤﻠﻴﻥ ﻤﺘﻤﺎﻴﺯﻴﻥ ﻫﻤﺎ ، x1 = ∆ −b+ = 1+ 3 = 4 = −2 2a )2× ( − 1 −2 x2 = ∆ −b− = 1− 3 −2 = +1 2a = )2×(−1 −2 3ﻨﻘﻁﺔ ﺍﻻﻨﻌﻁﺎﻑ ﺍﻟﺩﺍﻟﺔ f′ﺩﺍﻟﺔ ﻜﺜﻴﺭ ﺤﺩﻭﺩ ،ﻓﻬﻲ ﻗﺎﺒﻠﺔ ﻟﻼﺸﺘﻘﺎﻕ ﻋﻠﻰ ، IR ﻤﻥ ﺃﺠل ﻜل ﻋﺩﺩ xﻤﻥ IRﻟﺩﻴﻨﺎf′′(x)=-6x :
x ∞- ﻨﻠﺨﺹ ﻓﻲ ﺍﻟﺠﺩﻭل ﺍﻟﺘﺎﻟﻲ ﺇﺸﺎﺭﺓ )f′′(x )f′′(x ∞0 + +- ﺍﻟﺩﺍﻟﺔ f′′ﺘﻨﻌﺩﻡ ﻤﻥ ﺃﺠل ﺍﻟﻘﻴﻤﺔ x=0ﻭﻤﻨﻪ ﺍﻟﻨﻘﻁﺔ )) A(0,f(0ﻫﻲ ﻨﻘﻁﺔ ﺍﻨﻌﻁﺎﻑ ﻟﻠﻤﻨﺤﻨﻰ) (Cfﻭﺒﻤﺎ ﺃﻥ f(0)=-2ﻓﺈﻥ )A(0 , -2 4ﻤﻌﺎﺩﻟﺔ ﺍﻟﻤﻤﺎﺱ ﻋﻨﺩ ﺍﻟﻨﻘﻁﺔ A ﻭﻟﻴﻜﻥ )∆( ﻫﻭ ﺍﻟﻤﺴﺘﻘﻴﻡ ﺍﻟﻤﻤﺎﺱ )y=f′(0)(x-0)+f(0 ﻟﺩﻴﻨﺎ : ﻭﺒﻤﺎ ﺃﻥ f(0)= -2 :ﻭ f′(0) = 3 y= 3(x) -2 ﻓﺈﻥ : ﻭﻤﻨﻪ ﺍﻟﻤﺴﺘﻘﻴﻡ )∆( ﻤﻌﺎﺩﻟﺘﻪ ﺍﻟﺩﻴﻜﺎﺭﺘﻴﺔ y = 3x - 2 5ﺇﻨﺸﺎﺀ ﺍﻟﻤﻨﺤﻨﻰ )(Cf y 5 )∆( 4 )(Cf 3 2 1 →J →I-8 -7 -6 -5 -4 -3 -2 -1 0 12345678 x -1 -2 -3 -4 -5 -6 -7 = )g(x 2 x−3 ﺍﻟﺘﻤﺭﻴﻥ 13 −x+2 ﻟﺩﻴﻨﺎ : 1ﺩﺭﺍﺴﺔ ﺘﻐﻴﺭﺍﺕ ﺍﻟﺩﺍﻟﺔ g • ﻤﺠﻤﻭﻋﺔ ﺍﻟﺘﻌﺭﻴﻑ Dg ﺍﻟﺩﺍﻟﺔ gﻫﻲ ﺩﺍﻟﺔ ﺘﻨﺎﻅﺭﻴﺔ ،ﻭ ﻤﻌﺭﻓﺔ ﻋﻠﻰ} IR- {2ﺇﺫﻥ [∞Dg=]-∞,2[∪]2,+
• ﺤﺴﺎﺏ ﺍﻟﻨﻬﺎﻴﺎﺕ lim ( 2 x − 3 ) = lim ( 2 x/ ) = 2 = ﻟﺩﻴﻨﺎ − 2 : ∞→ − − x + 2 ∞→ − − x/ −1 x x lim ( 2 x − 3 ) = lim ( 2 x/ ) = 2 = −2 ﻭ ∞x → + − x + 2 ∞x → + − x/ −1 ﺤﺴﺎﺏ ) x lim g(xﻴﺅﻭل ﺇﻟﻰ 2 ﺇﺸﺎﺭﺓ ﺍﻟﻤﻘﺎﻡ )(-x+2∞x - ∞2 +-x + 2 + - {2 x − 3 → 1 ﻟﺩﻴﻨﺎ lim g ( x ) = −∞ :ﻷﻥ : − x+2→ 0− 〉 {2 x − 3→1 x→ 2 − x+ 2→ 0+ ﻟﺩﻴﻨﺎ lim g ( x ) = +∞ :ﻷﻥ: 〈 x→ 2 • ﺍﻟﺩﺍﻟﺔ ﺍﻟﻤﺸﺘﻘﺔﺍﻟﺩﺍﻟﺔ gﻫﻲ ﺤﺎﺼل ﻗﺴﻤﺔ ﺩﺍﻟﺘﻴﻥ ﻗﺎﺒﻠﺘﻴﻥ ﻟﻼﺸﺘﻘﺎﻕ ﻋﻠﻰ ، Dgﻓﻬﻲ ﻗﺎﺒﻠﺔ ﻟﻼﺸﺘﻘﺎﻕ ﻋﻠﻰ ، Dgﻭﻤﻨﻪ ﻤﻥ ﺃﺠل ﻜل ﻋﺩﺩ xﻤﻥ Dgﻟﺩﻴﻨﺎ :)g' (x = )(2 x −3)'(− x + 2)−( − x + 2)'( 2 x −3 (− x+ 2)2 )g' (x = )2( − x + 2) −( −1)( 2 x −3 ﻭﻤﻨﻪ (− x+2)2 )g' (x = −2 x + 4+ 2 x −3 (− x+ 2)2 1 ﺇﺫﻥ g' (x) = (−x+2)2 ﻭﻤﻨﻪ ﻤﻥ ﺍﺠل ﻜل xﻤﻥ Dgﻓﺈﻥ g′(x)>0
x ∞- 2 ﺇﺸﺎﺭﺓ )g′(x)g′(x + ∞+ + ﺇﺫﻥ gﻤﺘﺯﺍﻴﺩﺓ ﺘﻤﺎﻤﺎ ﻋﻠﻰ ﺍﻟﻤﺠﺎﻟﻴﻥ [] 2 , +∞[ ، ]-∞,2 • ﺠﺩﻭل ﺍﻟﺘﻐﻴﺭﺍﺕ x ∞- 2 ∞+ + +)g′(x)g(x +∞ -2 ∞ -2 - 2ﺍﻟﻤﺴﺘﻘﻴﻤﺎﺕ ﺍﻟﻤﻘﺎﺭﺒﺔ ﺒﻤﺎ ﺃﻥ lim g ( x ) = − 2ﻭ lim g ( x ) = − 2∞x → + ∞x → −ﺇﺫﻥ ﺍﻟﻤﻨﺤﻨﻰ ) (Cgﻴﻘﺒل ﺍﻟﻤﺴﺘﻘﻴﻡ ﺫﻭ ﺍﻟﻤﻌﺎﺩﻟﺔ y = −2ﻜﻤﺴﺘﻘﻴﻡ ﻤﻘﺎﺭﺏ ﻤﻭﺍﺯﻱ ﻟﺤﺎﻤل ﻤﺤﻭﺭ ﺍﻟﻔﻭﺍﺼل ∞lim g ( x ) = + ﻭ ﻭﺒﻤﺎ ﺃﻥ ∞lim g ( x ) = − 〉〈 x→ 2 x→ 2ﺇﺫﻥ ﺍﻟﻤﻨﺤﻨﻰ ) (Cgﻴﻘﺒل ﺍﻟﻤﺴﺘﻘﻴﻡ ﺫﻭ ﺍﻟﻤﻌﺎﺩﻟﺔ x = 2ﻜﻤﺴﺘﻘﻴﻡ ﻤﻘﺎﺭﺏ ﻤﻭﺍﺯﻱ ﻟﺤﺎﻤل ﻤﺤﻭﺭ ﺍﻟﺘﺭﺍﺘﻴﺏ 3ﺍﻟﻨﻘﻁﺔ ) W(2,-2ﻫﻲ ﻤﺭﻜﺯ ﺘﻨﺎﻅﺭ ﻟﻠﻤﻨﺤﻨﻰ )(Cg ﻨﻜﺘﺏ ﻤﻌﺎﺩﻟﺔ ﺍﻟﻤﻨﺤﻨﻰ ) (Cgﻓﻲ ﺍﻟﻤﻌﻠﻡ) ، (W , I , Jﺃﻱ ﻨﻀﻊ { {: x=X +2 ﻭﻤﻨﻪ x= X + x0 y=Y −2 y=Y + y0 ﻓﺈﻥ g(X+2)=Y-2 ﻭﺒﻤﺎ ﺃﻥ g(x)=y Y =−2 (2 X + 2)−3 = 2 X + 4−3 ﻭﻤﻨﻪ (− X + 2)+2 − X − 2+2 Y −2= 2 X +1 −X Y = 2 X +1+ 2= 2 X +1− 2 X ﺃﻱ ﺃﻥ −X −X
Y = 1 = −1 ﺇﺫﻥ −X Xh ( X )= −1 ﻟﺘﻜﻥ ﺍﻟﺩﺍﻟﺔ hﺍﻟﻤﻌﺭﻓﺔ ﻋﻠﻰ * IRﺒﺎﻟﺩﺴﺘﻭﺭ X ﻤﻥ ﺃﺠل ﻜل Xﻤﻥ * IRﻓﺈﻥ ) (-Xﻤﻥ *IR) h (− X )= −1 = − ( −1)= − h ( X ﻭﻟﺩﻴﻨﺎ −X Xﺃﻱ ﺃﻥ hﺩﺍﻟﺔ ﻓﺭﺩﻴﺔ ﻭﻤﻨﻪ ﻨﺴﺘﻨﺘﺞ ﺃﻥ ﺍﻟﻨﻘﻁﺔ ) W(2,-2ﻫﻲ ﻤﺭﻜﺯ ﺘﻨﺎﻅﺭ ﻟﻠﻤﻨﺤﻨﻰ )(Cg 4ﺍﻟﻤﻨﺤﻨﻰ) (Cgﻴﻘﺒل ﻤﻤﺎﺴﻴﻥ ﻤﻌﺎﻤل ﺘﻭﺠﻴﻬﻬﻤﺎ ﻴﺴﺎﻭﻱ 1ﻨﻌﻠﻡ ﺃﻥ ﻤﻌﺎﻤل ﺘﻭﺠﻴﻪ ﺍﻟﻤﺴﺘﻘﻴﻡ ﺍﻟﻤﻤﺎﺱ ﻓﻲ ﻨﻘﻁﺔ ﻟﻠﻤﻨﺤﻨﻰ) (Cgﻫﻭ ﺍﻟﻌﺩﺩ ﺍﻟﻤﺸﺘﻕ ﻟﻬﺫﻩ ﺍﻟﺩﺍﻟﺔ ﻋﻨﺩ ﻓﺎﺼﻠﺔ ﻫﺫﻩ ﺍﻟﻨﻘﻁﺔ g′(x) = 1 ﻨﻀﻊ(− x + 2)2 =1 ﺃﻱ 1 =1 ﻭﻤﻨﻪ x + 2)2 (− ﻭﻤﻨﻪ ) (-x+2=1ﺃﻭ )(-x+2= -1 ) (-x= -1ﺃﻭ )(-x = -3 ﺃﻱ ﺃﻥ ) (x= 1ﺃﻭ )(x= 3 ﺇﺫﻥ ﻤﻌﺎﺩﻟﺔ ﺍﻟﻤﻤﺎﺱ ﻋﻨﺩ ﺍﻟﻨﻘﻁﺔ ﺫﺍﺕ ﺍﻟﻔﺎﺼﻠﺔ x= 1 ﻭﻟﻴﻜﻥ )∆( ﻫﻭ ﺍﻟﻤﺴﺘﻘﻴﻡ ﺍﻟﻤﻤﺎﺱ )y=g′(1)(x-1)+g(1 ﻟﺩﻴﻨﺎ : g(1)= -1 ﻭﺒﻤﺎ ﺃﻥ : y= 1(x-1) -1 ﻓﺈﻥ :ﻭﻤﻨﻪ ﺍﻟﻤﺴﺘﻘﻴﻡ ﺍﻟﻤﻤﺎﺱ )∆( ﻤﻌﺎﺩﻟﺘﻪ ﺍﻟﺩﻴﻜﺎﺭﺘﻴﺔ y = x - 2 ﻤﻌﺎﺩﻟﺔ ﺍﻟﻤﻤﺎﺱ ﻋﻨﺩ ﺍﻟﻨﻘﻁﺔ ﺫﺍﺕ ﺍﻟﻔﺎﺼﻠﺔ x= 3 ﻭﻟﻴﻜﻥ ) (∆2ﻫﻭ ﺍﻟﻤﺴﺘﻘﻴﻡ ﺍﻟﻤﻤﺎﺱ )y=g′(3)(x-3)+g(3 ﻟﺩﻴﻨﺎ : ﻭﺒﻤﺎ ﺃﻥ g(3)= -3ﻓﺈﻥ y= 1(x-3) -3ﻭﻤﻨﻪ ﺍﻟﻤﺴﺘﻘﻴﻡ ﺍﻟﻤﻤﺎﺱ ) (Dﻤﻌﺎﺩﻟﺘﻪ ﺍﻟﺩﻴﻜﺎﺭﺘﻴﺔ y = x - 6
5ﺇﻨﺸﺎﺀ ﺍﻟﻤﻨﺤﻨﻰ ﻭﺍﻟﻤﻤﺎﺴﻴﻥ y 6 5 4 )∆( 3 2 1 →J )(D →J →I-8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8x -1 -2 )-3 (Cg -4 -5 -6 g(x)= x3-x ، f(x) = x3+2x-3 ﺍﻟﺘﻤﺭﻴﻥ 14 ﻟﺩﻴﻨﺎ 1ﺩﺭﺍﺴﺔ ﺘﻐﻴﺭﺍﺕ ﺍﻟﺩﺍﻟﺔ f • ﻤﺠﻤﻭﻋﺔ ﺍﻟﺘﻌﺭﻴﻑ Dflim x a ﺍﻟﺩﺍﻟﺔ fﻫﻲ ﺩﺍﻟﺔ ﻜﺜﻴﺭ ﺤﺩﻭﺩ ،ﻓﻬﻲ ﻤﻌﺭﻓﺔ ﻋﻠﻰ IRﺇﺫﻥ∞+ [∞Df=]−∞ ,+ • ﺤﺴﺎﺏ ﺍﻟﻨﻬﺎﻴﺎﺕ ∞lim x a f ( x ) = lim ( x 3 ) = − ∞−∞ − ∞f ( x ) = lim ( x 3 ) = + ∞+ • ﺍﻟﺩﺍﻟﺔ ﺍﻟﻤﺸﺘﻘﺔ ﺍﻟﺩﺍﻟﺔ fﺩﺍﻟﺔ ﻜﺜﻴﺭ ﺤﺩﻭﺩ ،ﻓﻬﻲ ﻗﺎﺒﻠﺔ ﻟﻼﺸﺘﻘﺎﻕ ﻋﻠﻰ ، IR ﻤﻥ ﺃﺠل ﻜل ﻋﺩﺩ xﻤﻥ IRﻟﺩﻴﻨﺎ f′(x) = 3x2+2 ﺇﺸﺎﺭﺓ ) f′(xﻤﻥ ﺃﺠل ﻜل ﻋﺩﺩ xﻤﻥ IRﻓﺈﻥ f′(x) >0 ﺇﺸﺎﺭﺓ ) f′(xﺘﻠﺨﺹ ﻓﻲ ﺍﻟﺠﺩﻭل ﺍﻟﺘﺎﻟﻲ ∞x - ∞+ f′(x) + ﺇﺫﻥ fﻤﺘﻨﺎﻗﺼﺔ ﺘﻤﺎﻤﺎ ﻋﻠﻰ IR
∞x - • ﺠﺩﻭل ﺍﻟﺘﻐﻴﺭﺍﺕ)f′(x ∞+)f(x + ∞- ∞+ 2ﺩﺭﺍﺴﺔ ﺘﻐﻴﺭﺍﺕ ﺍﻟﺩﺍﻟﺔ g • ﻤﺠﻤﻭﻋﺔ ﺍﻟﺘﻌﺭﻴﻑ Dg ﺍﻟﺩﺍﻟﺔ gﻫﻲ ﺩﺍﻟﺔ ﻜﺜﻴﺭ ﺤﺩﻭﺩ ،ﻓﻬﻲ ﻤﻌﺭﻓﺔ ﻋﻠﻰ IRﺇﺫﻥ ∞lim x a g ( x ) = lim ( x 3 ) = − [∞Dg=]−∞ ,+ ∞−∞ − • ﺤﺴﺎﺏ ﺍﻟﻨﻬﺎﻴﺎﺕ∞lim x a g ( x ) = lim ( x 3 ) = +∞+∞ + • ﺍﻟﺩﺍﻟﺔ ﺍﻟﻤﺸﺘﻘﺔ ﺍﻟﺩﺍﻟﺔ gﺩﺍﻟﺔ ﻜﺜﻴﺭ ﺤﺩﻭﺩ ،ﻓﻬﻲ ﻗﺎﺒﻠﺔ ﻟﻼﺸﺘﻘﺎﻕ ﻋﻠﻰ ، IR ﻤﻥ ﺃﺠل ﻜل ﻋﺩﺩ xﻤﻥ IRﻟﺩﻴﻨﺎ g′(x) = 3x2-1 : ﻟﺩﻴﻨﺎ g′(x)=0 :ﻴﻜﺎﻓﺊ ) (3x2-1=0ﻭﻤﻨﻪ 3x2=1(x = − 1 3 ) ( ﺃﻭ x = 1 3 ) ﻭﻤﻨﻪ x2 = 1 ﺇﺫﻥ 3 =− 3 =3 3 3 ﺇﺸﺎﺭﺓ ) g′(xﺘﻠﺨﺹ ﻓﻲ ﺍﻟﺠﺩﻭل ﺍﻟﺘﺎﻟﻲ x −3 3 ∞+ ∞- 3 3)g′(x +- +
∞x - −3 3 • ﺠﺩﻭل ﺍﻟﺘﻐﻴﺭﺍﺕ )g′(x 3 3 )g(x ∞+ + - + 2 3 3 ∞+ 9 −2 9 ∞- g ( − 3 ) = ( − 3 )3 − ( − 3 ) = − 3 3 + 93 = 63 = 2 3 27 27 27 3 3 3 9(g 3 3 ) 3 (− 3 33 93 = −6 3 = −2 3 (=) 3 3 =) 3 27 − 27 27 9 • 3ﻤﻌﺎﺩﻟﺔ ﺍﻟﻤﻤﺎﺱ)∆( ﻟﻠﻤﻨﺤﻨﻰ)(Cgﻋﻨﺩ ﺍﻟﻨﻘﻁﺔ ﺫﺍﺕ ﺍﻟﻔﺎﺼﻠﺔx=1 )y=g′(1)(x-1)+g(1 ﻟﺩﻴﻨﺎ : ﻭﺒﻤﺎ ﺃﻥ g′(1) = 2 ، g(1)= 0 : y= 2(x-1) +0 ﻓﺈﻥ : ﻭﻤﻨﻪ ﺍﻟﻤﺴﺘﻘﻴﻡ ﺍﻟﻤﻤﺎﺱ )∆( ﻤﻌﺎﺩﻟﺘﻪ ﺍﻟﺩﻴﻜﺎﺭﺘﻴﺔ y =2 x - 2 • ﻤﻌﺎﺩﻟﺔ ﺍﻟﻤﻤﺎﺱ)(Dﻟﻠﻤﻨﺤﻨﻰ)(Cfﻋﻨﺩ ﺍﻟﻨﻘﻁﺔ ﺫﺍﺕ ﺍﻟﻔﺎﺼﻠﺔ x=1 )y=f′(1)(x-1)+f(1 ﻟﺩﻴﻨﺎ : ﻭﺒﻤﺎ ﺃﻥ f(1)= 0 :ﻭ f′(1) = 5 y= 5(x-1) +0 ﻓﺈﻥ : ﻭﻤﻨﻪ ﺍﻟﻤﺴﺘﻘﻴﻡ ﺍﻟﻤﻤﺎﺱ) (Dﻤﻌﺎﺩﻟﺘﻪ ﺍﻟﺩﻴﻜﺎﺭﺘﻴﺔ y = 5x - 5 4ﻨﻘﻁ ﺘﻘﺎﻁﻊ ﺍﻟﻤﻨﺤﻨﻴﻴﻥ ) (Cfﻭ )(Cg )f(x) – g(x)=( x3+2x-3)- (x3-x ﻟﺩﻴﻨﺎ f(x)-g(x) = x3+2x-3- x3+x ﻭﻤﻨﻪ f(x)-g(x)= 3x-3 ﻟﺩﻴﻨﺎ f(x)-g(x)= 0ﻴﻜﺎﻓﺊ 3x-3 = 0 ﺃﻱ 3x=3ﻭﻤﻨﻪ x=1ﺇﺫﻥ })(Cf)∩(Cg)={B(1,0
6y 5ﺇﻨﺸﺎﺀ ﺍﻟﻤﻨﺤﻨﻴﻴﻥ ) (Cfﻭ )(Cg )5 (Cg )(D 4 3 4 5 6 7 8x 3 2 →J1→J →I-8 -7 -6 -5 -4 -3 -2 -1 0 1 2 -1 )(Cf -2 -3 )∆( -4 -5 -6 f ( x =) 3x+2 ﺍﻟﻤﺴﺄﻟﺔ 1 −x+3 ﻟﺩﻴﻨﺎ 1ﺩﺭﺍﺴﺔ ﺘﻐﻴﺭﺍﺕ ﺍﻟﺩﺍﻟﺔ f • ﻤﺠﻤﻭﻋﺔ ﺍﻟﺘﻌﺭﻴﻑ Df ﺍﻟﺩﺍﻟﺔ fﻤﻌﺭﻓﺔ ﻋﻠﻰ } IR-{3ﺃﻱ ﺃﻥ [∞Df=]-∞, 3[∪]3 ,+ • ﻋﻴﻴﻥ ﺍﻟﺜﻭﺍﺒﺕ a,b f ( x )= a + − b ﻟﺩﻴﻨﺎ ﻤﻥ ﺃﺠل ﻜل xﻤﻥ : Df x+3( x ) = a ( − x+3)+ b = − ax + 3 a + b ﺇﺫﻥ − x+3 − x+3{f ﻭﻤﻨﻪ ﺒﺎﻟﻤﻁﺎﺒﻘﺔ ﻤﻊ ﺩﺴﺘﻭﺭ ﺍﻟﺩﺍﻟﺔ fﻨﺠﺩ 3−aa+=b3=2 {a = −3 b =11 ﺇﺫﻥ f ( x =) −3+ 11 ﻭﻤﻨﻪ ) f(xﺘﻜﺘﺏ −x+3 • ﺤﺴﺎﺏ ﺍﻟﻨﻬﺎﻴﺎﺕ lim ( 3 x + 2 ) = lim ( 3 x/ ) = 3 = ﻟﺩﻴﻨﺎ − 3 : ∞x → − − x + 3 ∞x → − − x/ −1 lim ( 3 x + 2 ) = lim ( 3 x/ ) = 3 −3 ﻭ∞x → + − x + 3 ∞x → + − x/ = −1 ﺤﺴﺎﺏ ) lim f(xﻟﻤﺎ xﻴﺅﻭل ﺇﻟﻰ 3
x ∞- ﺇﺸﺎﺭﺓ ﺍﻟﻤﻘﺎﻡ )(-x+3-x + 3 + ∞3 + - {3 x + 2 →11 ﻟﺩﻴﻨﺎ lim f ( x ) = −∞ :ﻷﻥ : − x+3→ 0− 〉 {3 x + 2 →11 − x+3→ 0+ x→3 ﻟﺩﻴﻨﺎ lim f ( x ) = +∞ :ﻷﻥ: 〈 x→3 • ﺍﻟﺩﺍﻟﺔ ﺍﻟﻤﺸﺘﻘﺔﺍﻟﺩﺍﻟﺔ fﻫﻲ ﺤﺎﺼل ﻗﺴﻤﺔ ﺩﺍﻟﺘﻴﻥ ﻗﺎﺒﻠﺘﻴﻥ ﻟﻼﺸﺘﻘﺎﻕ ﻋﻠﻰ ، Dfﻓﻬﻲ ﻗﺎﺒﻠﺔ ﻟﻺﺸﺘﻘﺎﻕ ﻋﻠﻰ ، Dfﻭﻤﻨﻪ ﻤﻥ ﺃﺠل ﻜل ﻋﺩﺩ xﻤﻥ Dfﻟﺩﻴﻨﺎ :)f '(x = ) ( 3 x + 2 )' ( − x + 3 ) − ( − x + 3 )' ( 3 x + 2 (− x+3)2 )f ' (x = )3( − x +3)− ( −1)(3 x + 2 ﻭﻤﻨﻪ (− x+3)2)f ' (x = −3x+9+3x+2 (− x+3)2 )f ' (x = 11 ﺇﺫﻥ (− x+3)2 ﻭﻤﻨﻪ ﻤﻥ ﺍﺠل ﻜل xﻤﻥ Dfﻓﺈﻥ f′(x)>0 ﺇﺸﺎﺭﺓ )f′(x x -∞ 3 ∞+)f′(x ++ ﺇﺫﻥ fﻤﺘﺯﺍﻴﺩﺓ ﺘﻤﺎﻤﺎ ﻋﻠﻰ ﺍﻟﻤﺠﺎﻟﻴﻥ [] 3 , +∞[ ، ]-∞,3
∞x - • ﺠﺩﻭل ﺍﻟﺘﻐﻴﺭﺍﺕf′(x) + ∞3 +)f(x + -3 +∞ -3 ∞− 2ﺍﻟﻤﺴﺘﻘﻴﻤﺎﺕ ﺍﻟﻤﻘﺎﺭﺒﺔ ﺒﻤﺎ ﺃﻥ lim f ( x ) = −3ﻭ lim f ( x ) = −3∞x → + ∞x → −ﺇﺫﻥ ﺍﻟﻤﻨﺤﻨﻰ ) (Cfﻴﻘﺒل ﺍﻟﻤﺴﺘﻘﻴﻡ ﺫﻭ ﺍﻟﻤﻌﺎﺩﻟﺔ y = −3ﻜﻤﺴﺘﻘﻴﻡ ﻤﻘﺎﺭﺏ ﻤﻭﺍﺯﻱ ﻟﺤﺎﻤل ﻤﺤﻭﺭ ﺍﻟﻔﻭﺍﺼل ﻭ ∞lim f ( x ) = + ﻭﺒﻤﺎ ﺃﻥ ∞lim f ( x ) = − 〉〈 x→3 x→3ﺇﺫﻥ ﺍﻟﻤﻨﺤﻨﻰ ) (Cfﻴﻘﺒل ﺍﻟﻤﺴﺘﻘﻴﻡ ﺫﻭ ﺍﻟﻤﻌﺎﺩﻟﺔ x = 3ﻜﻤﺴﺘﻘﻴﻡ ﻤﻘﺎﺭﺏ ﻤﻭﺍﺯﻱ ﻟﺤﺎﻤل ﻤﺤﻭﺭ ﺍﻟﺘﺭﺍﺘﻴﺏ 3ﺍﻟﻨﻘﻁﺔ ) W(3,-3ﻫﻲ ﻤﺭﻜﺯ ﺘﻨﺎﻅﺭ ﻟﻠﻤﻨﺤﻨﻰ )(Cf ﻨﻜﺘﺏ ﻤﻌﺎﺩﻟﺔ ﺍﻟﻤﻨﺤﻨﻰ ) (Cfﻓﻲ ﺍﻟﻤﻌﻠﻡ ، w , I , Jﺃﻱ ﻨﻀﻊ ( ): { {x = X + 3 y=Y −3 ﻭﻤﻨﻪ x= X + x0 y=Y + y0 ﻓﺈﻥ f(X+3)=Y-3 ﻭﺒﻤﺎ ﺃﻥ f(x)=yY −3 = 3( X +3)+2 = 3X +9+2 ﻭﻤﻨﻪ −( X +3)+3 − X −3+3 Y −3 = 3 X +11 −X Y = 3 X +11 + 3 = 3 X +11 − 3 X ﺃﻱ ﺃﻥ −X −X 11 −11 ﺇﺫﻥ Y = −X = X ) h(X = −11 ﻟﺘﻜﻥ ﺍﻟﺩﺍﻟﺔ hﺍﻟﻤﻌﺭﻓﺔ ﻋﻠﻰ * IRﺒﺎﻟﺩﺴﺘﻭﺭ X
ﻤﻥ ﺃﺠل ﻜل Xﻤﻥ * IRﻓﺈﻥ ) (-Xﻤﻥ *IR= ) h(− X − 11 = − ( − 11 ) = ) −h(X ﻭﻟﺩﻴﻨﺎ −X Xﺃﻱ ﺃﻥ hﺩﺍﻟﺔ ﻓﺭﺩﻴﺔ ﻭﻤﻨﻪ ﻨﺴﺘﻨﺘﺞ ﺃﻥ ﺍﻟﻨﻘﻁﺔ ) W(3,-3ﻫﻲ ﻤﺭﻜﺯ ﺘﻨﺎﻅﺭ ﻟﻠﻤﻨﺤﻨﻰ )(Cf 4ﺍﻟﻤﻨﺤﻨﻰ) (Cfﻴﻘﺒل ﻤﻤﺎﺴﻴﻥ ﻤﻌﺎﻤل ﺘﻭﺠﻴﻬﻬﻤﺎ ﻴﺴﺎﻭﻱ 1ﻨﻌﻠﻡ ﺃﻥ ﻤﻌﺎﻤل ﺘﻭﺠﻴﻪ ﺍﻟﻤﺴﺘﻘﻴﻡ ﺍﻟﻤﻤﺎﺱ ﻓﻲ ﻨﻘﻁﺔ ﻟﻠﻤﻨﺤﻨﻰ) (Cfﻫﻭ ﺍﻟﻌﺩﺩ ﺍﻟﻤﺸﺘﻕ ﻟﻬﺫﻩ ﺍﻟﺩﺍﻟﺔ ﻋﻨﺩ ﻓﺎﺼﻠﺔ ﻫﺫﻩ ﺍﻟﻨﻘﻁﺔ f′(x) = 1 ﻨﻀﻊ 11 =11 ﻤﻥ ﺃﺠل ﻜل xﻤﻥ Dfﻟﺩﻴﻨﺎ x+3)2 (− ﻭﻤﻨﻪ ﺒﻌﺩ ﺍﺨﺘﺯﺍل ﺍﻟﻌﺩﺩ 11ﻤﻥ ﺍﻟﻁﺭﻓﻴﻥ ﻨﺠﺩ (-x+3)2=1 ﻭﻤﻨﻪ ) (-x+3= 1ﺃﻭ )(-x+3 = -1 ﻭﻤﻨﻪ ) (-x =-2ﺃﻭ )(-x = -4 ﺇﺫﻥ ) ( x= 2ﺃﻭ )(x = 4 ﻤﻌﺎﺩﻟﺔ ﺍﻟﻤﻤﺎﺱ ﻋﻨﺩ ﺍﻟﻨﻘﻁﺔ ﺫﺍﺕ ﺍﻟﻔﺎﺼﻠﺔ x= 2 ﻭﻟﻴﻜﻥ ) (Lﻫﻭ ﺍﻟﻤﺴﺘﻘﻴﻡ ﺍﻟﻤﻤﺎﺱ )y=f′(2)(x-2)+f(2 ﻟﺩﻴﻨﺎ : ﻭﻟﺩﻴﻨﺎ f(2)= 8 y=11(x-2)+8 ﻓﺈﻥ y=11x -22 + 8 ﺇﺫﻥ ﻭﻤﻨﻪ ﺍﻟﻤﺴﺘﻘﻴﻡ ﺍﻟﻤﻤﺎﺱ ) (Lﻤﻌﺎﺩﻟﺘﻪ ﺍﻟﺩﻴﻜﺎﺭﺘﻴﺔ y = 11x - 14 ﻤﻌﺎﺩﻟﺔ ﺍﻟﻤﻤﺎﺱ ﻋﻨﺩ ﺍﻟﻨﻘﻁﺔ ﺫﺍﺕ ﺍﻟﻔﺎﺼﻠﺔ x= 4 ﻭﻟﻴﻜﻥ ) (Dﻫﻭ ﺍﻟﻤﺴﺘﻘﻴﻡ ﺍﻟﻤﻤﺎﺱ )y=f′(4)(x-4)+f(4 ﻟﺩﻴﻨﺎ : ﻭﻟﺩﻴﻨﺎ f(4)= -14 y=11(x-4)-14 ﻓﺈﻥ y=11x -44 - 14 ﺇﺫﻥ y = 11x - 58 ﻭﻤﻨﻪ ﺍﻟﻤﺴﺘﻘﻴﻡ ﺍﻟﻤﻤﺎﺱ ) (Dﻤﻌﺎﺩﻟﺘﻪ ﺍﻟﺩﻴﻜﺎﺭﺘﻴﺔ
5ﻨﻘﻁ ﺘﻘﺎﻁﻊ )∆( ﻤﻊ )(Cf )∆( ﻤﺴﺘﻘﻴﻡ ﻤﻌﺎﺩﻟﺘﻪ y=-3x -2 3 x + 2 = − 3 x − 2 f(x)=yﻭﻤﻨﻪ ﻨﻀﻊ − x + 3 )3x+2 = (-x+3)(-3x-2 ﺇﺫﻥ )3x+2 = -(-x+3)(3x+2 3x+2 +(-x+3)(3x+2) =0 ﻭﻤﻨﻪ (3x+2)(1-x+3)=0 ﺇﺫﻥ (3x+2)( -x+4)=0 ) (3x+2=0ﺃﻭ ) (-x+4=0 ﺃﻱ ﺇﺫﻥ ={ }(x )4 ﺃﻭ ( x = − 2 ) 3 ﺇﺫﻥ = )∆( ∩ ) (C B ( 4 , − 14 ), B ' ( − 2 , 0 ) f 3 ﻭﻀﻌﻴﺔ )∆( ﺒﺎﻟﻨﺴﺒﺔ ﻟـ )(Cfx ∞- − 2 ∞4 + 3ﺍﻟﻔﺭﻕ f(x)-y -+ - ﺍﻟﻭﻀﻌﻴﺔ )∆(ﻴﻘﻊ ﻓﻭﻕ ) (∆) (Cfﻴﻘﻊ ﺘﺤﺕ) (∆) (Cfﻴﻘﻊ ﻓﻭﻕ)(Cf 6ﺍﻹﻨﺸﺎﺀ y 8 )∆( 7 )(x=3 6 )(D 5 4 3 2 →J→1 I-17-16-15-14-13-12-11-10-9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 x -1 -2 -3 )(y=-3 -4 -5 -6 -7 )(Cf -8 -9 -10 -11 -12 )(L -13 -14 -15 -16
g(x)=3x2-9x-3 ﺍﻟﻤﺴﺄﻟﺔ 2 ﻟﺩﻴﻨﺎ f(x)=x3-x2-x-3 :ﻭ 1ﺩﺭﺍﺴﺔ ﺘﻐﻴﺭﺍﺕ ﺍﻟﺩﺍﻟﺔ f • ﻤﺠﻤﻭﻋﺔ ﺍﻟﺘﻌﺭﻴﻑ Df ﺍﻟﺩﺍﻟﺔ fﻫﻲ ﺩﺍﻟﺔ ﻜﺜﻴﺭﺤﺩﻭﺩ ،ﻓﻬﻲ ﻤﻌﺭﻓﺔ ﻋﻠﻰ IRﺇﺫﻥ [∞Df=]−∞ ,+lim x a ∞f ( x ) = lim ( x 3 ) = − ﺤﺴﺎﺏ ﺍﻟﻨﻬﺎﻴﺎﺕ∞− ∞−lim x a∞+ ∞f ( x ) = lim ( x 3 ) = + ∞+ • ﺍﻟﺩﺍﻟﺔ ﺍﻟﻤﺸﺘﻘﺔ ﺍﻟﺩﺍﻟﺔ fﺩﺍﻟﺔ ﻜﺜﻴﺭ ﺤﺩﻭﺩ ،ﻓﻬﻲ ﻗﺎﺒﻠﺔ ﻟﻼﺸﺘﻘﺎﻕ ﻋﻠﻰ ، IR ﻤﻥ ﺃﺠل ﻜل ﻋﺩﺩ xﻤﻥ IRﻟﺩﻴﻨﺎ f′(x) = 3x2+6x-9 : 3x2-2x-1=0 ﻟﺩﻴﻨﺎ f′(x)=0 :ﻴﻜﺎﻓﺊ ﺤﺴﺎﺏ ﺍﻟﻤﻤﻴﺯ∆ ﻟﻨﺎ ∆=b2-4ac=(-2)2-4(3)(-1)=4+12=16= x1 −b+ ∆ = 2+4 = 6 = 1 ﻭﻤﻨﻪ ﻟﻠﻤﻌﺎﺩﻟﺔ ﺤﻠﻴﻥ ﻤﺘﻤﺎﻴﺯﻴﻥ: 2a 2×3 6 x2 = −b+ ∆ = 2−4 = −2 = −1 2a 2×3 6 3 ﺇﺸﺎﺭﺓ ) f′(xﺘﻠﺨﺹ ﻓﻲ ﺍﻟﺠﺩﻭل ﺍﻟﺘﺎﻟﻲ∞x - −1 1 ∞+ 3f′(x) + - +∞x - −1 1 • ﺠﺩﻭل ﺍﻟﺘﻐﻴﺭﺍﺕ)f′(x 3)f(x - ∞+ + + 76 ∞+ − 27 -4 ∞-
f(1)=13 –(1)2-1-3=-4 f (− 1) = − 76 3 27 ﺩﺭﺍﺴﺔ ﺘﻐﻴﺭﺍﺕ ﺍﻟﺩﺍﻟﺔ g • ﻤﺠﻤﻭﻋﺔ ﺍﻟﺘﻌﺭﻴﻑ Dg ﺍﻟﺩﺍﻟﺔ gﻫﻲ ﺩﺍﻟﺔ ﻜﺜﻴﺭ ﺤﺩﻭﺩ ،ﻓﻬﻲ ﻤﻌﺭﻓﺔ ﻋﻠﻰ IRﺇﺫﻥ [∞Dg=]−∞ ,+lim x a ∞g ( x ) = lim ( 3 x 2 ) = + ﺤﺴﺎﺏ ﺍﻟﻨﻬﺎﻴﺎﺕ∞− ∞−lim x a ∞g ( x ) = lim ( 3 x 2 ) = +∞+ ∞+ • ﺍﻟﺩﺍﻟﺔ ﺍﻟﻤﺸﺘﻘﺔ ﺍﻟﺩﺍﻟﺔ gﺩﺍﻟﺔ ﻜﺜﻴﺭ ﺤﺩﻭﺩ ،ﻓﻬﻲ ﻗﺎﺒﻠﺔ ﻟﻼﺸﺘﻘﺎﻕ ﻋﻠﻰ ، IR ﻤﻥ ﺃﺠل ﻜل ﻋﺩﺩ xﻤﻥ IRﻟﺩﻴﻨﺎ g′(x) = 6x-9 : =x 9 = 3 ﻟﺩﻴﻨﺎ g′(x)=0 :ﻴﻜﺎﻓﺊ 6x-9 = 0وﻣﻨﻪ 6x = 9إذن 6 2 ﺇﺸﺎﺭﺓ ) g′(xﺘﻠﺨﺹ ﻓﻲ ﺍﻟﺠﺩﻭل ﺍﻟﺘﺎﻟﻲ∞x - 3 ∞2 +)g′(x + -∞x - 3 • ﺠﺩﻭل ﺍﻟﺘﻐﻴﺭﺍﺕ 2)g′(x - ∞+)g(x −39 ∞+ 4 + ∞+ g ( (32 )=3 3 )2 (−9 3 =)−3 27 − 27 −142 = −39 2 2 4 2 4
2ﻋﻴﻥ ﻨﻘﻁﺔ ﺘﻘﺎﻁﻊ ) (Cﻤﻊ )(ϕ )f(x)=g(x ﻨﻀﻊ x3+3x2-9x-11 = 3x2-9x-3 ﻭﻤﻨﻪ x3-4x2-8x=0 ﺒﻌﺩ ﺍﻻﺨﺘﺯﺍل ﻨﺠﺩ ﻭﻤﻨﻪ x(x2-4x+8)=0ﺇﺫﻥ ) (x=0ﺃﻭ )(x2-4x+8=0 ﺤل ﺍﻟﻤﻌﺎﺩﻟﺔ x2-4x-8=0ﻭﻤﻨﻪ ﻟﻴﺱ ﻟﻠﻤﻌﺎﺩﻟﺔ ﺤل ﻓﻲIR ﺤﺴﺎﺏ ﺍﻟﻤﻤﻴﺯ ∆ ∆=(-4)2-4(-8)=-16 ﺇﺫﻥ })(C)∩ (ϕ)={A(0,-3 3ﻤﻌﺎﺩﻟﺔ ﺍﻟﻤﻤﺎﺴﻴﻥ ﻟـ )(Cﻭ ) (ϕﻋﻨﺩ ﺍﻟﻨﻘﻁﺔ Aﺫﺍﺕ ﺍﻟﻔﺎﺼﻠﺔ 0 ﻟﻴﻜﻥ ) (Lﻫﻭ ﺍﻟﻤﺴﺘﻘﻴﻡ ﺍﻟﻤﻤﺎﺱ ﻟـ ) (Cﻋﻨﺩ A )y=f′(0)(x-0)+f(0 ﻟﺩﻴﻨﺎ : f′(0)=-1, f(0)=- 3 ﻭﻟﺩﻴﻨﺎ ﻓﺈﻥ y=-(x)-3ﺇﺫﻥ y=-x-3 ﻟﻴﻜﻥ ) ( Dﻫﻭ ﺍﻟﻤﺴﺘﻘﻴﻡ ﺍﻟﻤﻤﺎﺱ ﻟـ ) (ϕﻋﻨﺩ A )y=g′(0)(x-0)+g(0 ﻟﺩﻴﻨﺎ : g′(0)=-9 , g(0)=- 3 ﻭﻟﺩﻴﻨﺎ y=-9x-3 y=-9x-3ﺇﺫﻥ ﻓﺈﻥ 4ﺍﻹﻨﺸﺎﺀ y2(∆) 1 →I )(ϕ →J-8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9x-1-2-3-4-5 -6 )(L)(C -7 -8-9-10
5ﺍﻟﺤل ﺍﻟﺒﻴﺎﻨﻲ ﻨﻼﺤﻅ ﻤﻥ ﺍﻟﺒﻴﺎﻥ ﺃﻥ ) f (x)〉 g(xﻤﻥ ﺃﺠل xﻤﻥ ﺍﻟﻤﺠﺎل ∞] [0,+ ﺍﻟﻤﺴﺄﻟﺔ 1 (g x)=(− 1 ) x2 +13x−5000 1ﻟﺩﻴﻨﺎ 200 • ﺍﻟﺩﺍﻟﺔ gﻫﻲ ﺩﺍﻟﺔ ﻜﺜﻴﺭ ﺤﺩﻭﺩ ،ﻓﻬﻲ ﻤﻌﺭﻓﺔ ﻋﻠﻰ IR • ﺤﺴﺎﺏ ﺍﻟﻨﻬﺎﻴﺎﺕ lim →x f ( =)x lim (− 1 )x2 ∞=− ∞− ∞x→− 200 lim →x f =)(x lim (− 1 ) x2 ∞=− ∞+ ∞x→+ 200 • ﻋﺒﺎﺭﺓ ﺍﻟﺩﺍﻟﺔ ﺍﻟﻤﺸﺘﻘﺔ ﺍﻟﺩﺍﻟﺔ gﻫﻲ ﺩﺍﻟﺔ ﻜﺜﻴﺭ ﺤﺩﻭﺩ ،ﻓﻬﻲ ﻗﺎﺒﻠﺔ ﻟﻼﺸﺘﻘﺎﻕ ﻋﻠﻰ IR ﻭﻟﺩﻴﻨﺎ g'(x)=−1010 x+13 ﺇﺸﺎﺭﺓ ) g′(xﺘﻠﺨﺹ ﻓﻲ ﺍﻟﺠﺩﻭل ﺍﻟﺘﺎﻟﻲ x −∞ 1300 ∞+)g′(x +- ∞x - + 1300 • ﺠﺩﻭل ﺍﻟﺘﻐﻴﺭﺍﺕ)g′(x 3450 ∞+)g(x - ∞-∞ - 2ﺃ -ﺇﺜﺒﺎﺕ ﺃﻥ ﺍﻟﻔﺎﺌﺩﺓ ﺍﻟﻴﻭﻤﻴﺔ – ﻤﻘﺩﺭﺓ ﺒﺎﻟﺩﻨﺎﻨﻴﺭ -ﻫﻲ B ( x =) ( − 1 ) x 2 +13 x − 5000 200
ﻟﺩﻴﻨﺎ ﺍﻟﻔﺎﺌﺩﺓ ﺍﻟﻴﻭﻤﻴﺔ =ﺍﻟﺜﻤﻥ ﺍﻟﻜﻠﻲ ﻟﻠﻤﺼﺎﺒﻴﺢ ﺍﻟﻤﺒﺎﻋﺔ – ﺘﻜﻠﻔﺔ ﺍﻹﻨﺘﺎﺝB ( x ) =17 x − C ( x ) =17 x − ( 1 x 2 + 4 x + 5000 ) ﻭﻤﻨﻪ 200B ( x ) =17 x − C ( x ) =17 x − 1 x 2 − 4 x −5000 200 B ( x ) = ( − 1 ) x 2 + 13 x − 5000 ﺇﺫﻥ 200 ﻭﻤﻨﻪ ﺼﺤﺔ ﺍﻟﻤﺴﺎﻭﺍﺓﺏ -ﻋﺩﺩ ﺍﻟﻤﺼﺎﺒﻴﺢ ﺍﻟﺫﻱ ﻴﺠﺏ ﺇﻨﺘﺎﺠﻪ ﻫﻭ ﻗﻴﻤﺔ xﺍﻟﺘﻲ ﻤﻥ ﺃﺠﻠﻬﺎ ﺘﻜﻭﻥ ﻟﺩﻴﻨﺎ ﻗﻴﻤﺔ ﺤﺩﻴﺔ ﻋﻅﻤﻰ ،ﻭﻟﺩﻴﻨﺎﻤﻥ ﺃﺠل x=1300ﻓﺈﻥ ﺍﻟﻌﺩﺩ f(1300)= 3450ﻴﻤﺜل ﻗﻴﻤﺔ ﺤﺩﻴﺔ ﻋﻅﻤﻰ ﺃﻱ ﺃﻥ ﻋﺩﺩ ﺍﻟﻤﺼﺎﺒﻴﺢ ﺍﻟﺫﻱ ﻴﺠﺏ ﺇﻨﺘﺎﺠﻪ ﻫﻭ x=1300ﺍﻟﺫﻱ ﻨﺤﺼل ﺒﻪ ﻋﻠﻰ ﺍﻟﻤﺒﻠﻎ 3450ﺩﻴﻨﺎﺭﺍ
ﺘﻤﺎﺭﻴﻥ ﻭﻤﺸﻜﻼﺕ ﺤﻭل ﺍﻟﺩﻭﺍل ﺍﻟﺘﻤﺭﻴﻥ01 ﺍﻟﺭﺒﻁ ﺒﻴﻥ ﺇﺸﺎﺭﺓ ﺍﻟﺩﺍﻟﺔ ﺍﻟﻤﺸﺘﻘﺔ ﻭﺠﺩﻭل ﺘﻐﻴﺭﺍﺘﻬﺎ ﺍﻨﻘل ﻭﺃﻜﻤل ﺠﺩﻭل ﺘﻐﻴﺭﺍﺕ ﺍﻟﺩﺍﻟﺔ fﻗﺎﺒﻠﺔ ﻟﻼﺸﺘﻘﺎﻕ ﻋﻠﻰ ﺍﻟﻤﺠﺎل][-2,5x -2 0 2 5)f′(xf(x) 3 1 X -3 -2 ﺍﻟﺘﻤﺭﻴﻥ : 02ﻨﻔﺱ ﺴﺅﺍل ﺍﻟﺘﻤﺭﻴﻥ ﺍﻷﻭلf′(x) + 0 13)f(x + -1
ﺍﻟﺘﻤﺭﻴﻥ: 03 1ﺍﻨﻘل ﻭﺃﻜﻤل ﺠﺩﻭل ﺘﻐﻴﺭﺍﺕ ﺍﻟﺩﺍﻟﺔ fﺍﻟﺘﺎﻟﻲ:ﻋﻠﻤﺎ ﺃﻥ f(1)=1ﻭf(6)=4X -2 1 3 6f′(x) +f(x) 2 2ﺤﺩﺩ ﺇﺸﺎﺭﺓ ) f′(0ﻭ )f(0 3ﻤﺎﻩ ﻱ ﺇﺸﺎﺭﺓ )f(xﻋﻠل ﺒﺈﺠﺎﺒﺘﻙ ﺍﻟﺘﻤﺭﻴﻥ : 04 ﺍﻟﺭﺒﻁ ﺒﻴﻥ ﺠﺩﻭل ﺍﻟﺘﻐﻴﺭﺍﺕ ﻭﺍﻟﻤﺴﺘﻘﻴﻤﺎﺕ ﺍﻟﻤﻘﺎﺭﺒﺔﻻﺤﻅ ﺠﺩﻭل ﺘﻐﻴﺭﺍﺕ ﺍﻟﺩﺍﻟﺔ fﺍﻟﺘﺎﻟﻲ ﺜﻡ ﻋﻴﻥ ﻤﻌﺎﺩﻻﺕ ﺍﻟﻤﺴﺘﻘﻴﻤﺎﺕ ﺍﻟﻤﻘﺎﺭﺒﺔ ﺍﻟﻤﻭﺍﺯﻴﺔ ﻟﻠﻤﺤﻭﺭﻴﻥ∞x - -2 0 ∞+)f′(x +- - ∞+∞ +f(x) 2 ∞-∞ - 3 -ﺤﺩﺩ ﻤﻌﺎﺩﻟﺔ ﻜل ﻤﺴﺘﻘﻴﻡ ﻤﻘﺎﺭﺏ ﺘﻼﺤﻅﻪ ﻤﻊ ﺍﻟﺘﺤﻠﻴل
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