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Suatu fungsi dirumuskan dengan
f(x) = ax² + bx + c. Jika
f(1) = 6, f'(0) = 2, dan f'(1) = 4,
nilai 2a + b + 3c adalah berapa?

13  ✔️

Kenapa 13?
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f(x) = ax² + bx + c
f(1) = 6
6 = (1)²a + 1b + c
a + b + c = 6
-------------------------
f'(0) = 2
f(x) = ax² + bx + c
f'(x) = 2ax + b
f'(0) = 2
2 = 2a(0) + b
b = 2
-------------------------
Dengan
f'(x) = 2ax + b
f'(1) = 4
4 = 2a(1) + b
4 = 2a + 2
2a = 4 - 2
2a = 2
a = 2/2
a = 1
-------------------------
a + b + c = 6
1 + 2 + c = 6
c = 6 - 1 - 2
c = 5 - 2
c = 3
-------------------------
nilai 2a + b + 3c =
2(1) + 2 + 3(3) =
2 + 2 + 9 =
13 ✔️
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xcvi