Buat kaka yang pinter matematika mohon dibantu beserta caranya yah kak, soal essay. No spam yah, terimakasih.
Matematika
Yann4
Pertanyaan
Buat kaka yang pinter matematika mohon dibantu beserta caranya yah kak, soal essay. No spam yah, terimakasih.
2 Jawaban
-
1. Jawaban DB45
Turunan
1. y= x + √(p-x) --> y = x + (p-x)¹/²
a. y' = 1 + ¹/₂ (-1) (p-x)⁻¹/²
y' = 1 - 1 /(2√(p-x)
b. Nilai maksimum jika y' = 0
1 - 1/(2√(p-x)) = 0
1/ (2√(p-x))= 1
2 √(p-x) = 1
√(p-x) = ¹/₂
p - x = (¹/₂)² .....(1)
f(x)= 4
x + √(p-x) = 4
√(p-x) = 4 - x
p - x = (4- x)²...(2)
.
(2) = (1)
(4-x)² = (¹/₂)²
4 - x = ¹/₂
x = 4 - ¹/₂
x = 3¹/₂
p = (¹/₂)² + x
p = ¹/₄ + 3 ¹/₂
p = 3 ³/₄
c. f(x)= x + √(3 ³/₄ - x)
f(3) = 3 + √(3³/₄ -3)
f(3) = 3 + √(³/₄)
f(3) = 3 + ¹/₂ √3
2. f(x) = ¹/₃ x³ + ¹/₂ x² -2x + 3
a. f'(x) = x² + x - 2
b. interval fungsi naik dan fungsi turun
fungsi naik f';(x) < 0
x² + x -2 < 0
(x+2)(x-1) < 0
x > -2 atau x < 1
interval -2 < x < 1
fungsi naik f '(x) > 0
x² +x - 2 > 0
(x+2)(x -1) > 0
x < -2 atau x > 1
c. f ' (x) = x² + x - 2
f " (x) = 2x + 1
d. syarat titik belok belok f'(x) = 0 . dan f " (x ) = 0
f'(x) = 0 --> x² + x- 2 = 0
(x +2)(x -1) = 0
x= - 2 ,, x = 1
f " (x)= 2x + 1
f" (-2) = 2(-2) + 1 = -3
f " (1)= 2(1) + 1 = 1
f " (x) ≠ 0
tidak ada titik belok
gambar dilampiran2. Jawaban whongaliem
[tex]y = f (x) = x + \sqrt{p - x} [/tex]
[tex]= x + (p - x)^{ \frac{1}{2} } [/tex]
[tex]a) f' (x) = 1 - \frac{1}{2} (p - x)^{ - \frac{1}{2} } [/tex]
[tex]= 1 - \frac{1}{2} \frac{1}{ \sqrt{p - x} } [/tex]
[tex]= 1 + \frac{1}{2 (p - x)} \sqrt{p - x} [/tex]
b) nilai maksimum terjadi jika f' (x) = 0
[tex]0 = 1 - \frac{1}{2} (p - x)^{ - \frac{1}{2} } [/tex]
[tex]- 1 = - \frac{1}{2} (p - x)^{ -\frac{1}{2} } [/tex]
[tex]2 = (p - x)^{ - \frac{1}{2} } ..... kedua ruas pangkat dengan - 2[/tex]
[tex] \frac{1}{4} = p - x[/tex]
[tex]x = p - \frac{1}{4} .... subtitusi f (x) denga f (x) = 4[/tex]
[tex]4 = p - \frac{1}{4} + \sqrt{p - (p - \frac{1}{4} )} [/tex]
[tex]4 = p - \frac{1}{4} + \sqrt{ \frac{1}{4} } [/tex]
[tex]4 = p - \frac{1}{4} + \frac{1}{2} [/tex]
[tex]4 = p - \frac{1}{2} [/tex]
[tex]p = 4 + \frac{1}{2} [/tex]
[tex]p = \frac{9}{2} [/tex]
c) [tex]f' (x) = 1 - \frac{1}{2 (p - x)} \sqrt{p - x} [/tex]
[tex]= 1 - \frac{1}{2( \frac{9}{2}- x) } \sqrt{ \frac{9}{2} - x} [/tex]
[tex]= 1 - \frac{1}{9 - 2x} \sqrt{ \frac{9}{2} - x} [/tex]
[tex]f' (3) = 1 - \frac{1}{9 - 2(3)} \sqrt{ \frac{9}{2} - 3} [/tex]
[tex]= 1 - \frac{1}{3} \sqrt{ \frac{3}{2} } [/tex]
[tex]= 1 - \frac{1}{6} \sqrt{6} [/tex]
2) f (x) = 1/3.x³ + 1/2 x² - 2x + 3
a) f' (x) = x² + x - 2
b) interval naik ⇒ f' (x) > 0
x² + x - 2 > 0
(x + 2)(x - 1) > 0
kurva naik pada interval { - 2 < x atau x > 1}
interval turun ⇒ f' (x) < 0
(x + 2) (x - 1) < 0
kurva turun pada interval : { x / - 2 < x < 1}
c) f' (x) = x² + x - 2
f" (x) = 2x + 1
d) syarat titik belok f" (x) = 0
f " (x) = 2x - 1
0 = 2x - 1
2x = 1
x = 1/2
karena x = 1/2 berada pada interval turun makan kurva tak mempunyai titik belok
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