Mohon bantuannya. Terimakasih teman teman.

f(x) = 20x^(7/2) + 2x^(5/2) + 10x
f'(x) = 70x^(5/2) + 5x^(3/2) + 10
f''(x) = 175x^(3/2) + (15/2) x^(1/2)
f''(4) = 175 (4)^(3/2) + 15/2 (4)^(1/2)
= 175 (2^2)^(3/2) + 15/2 (2^2)^(1/2)
= 175 . 2^3 + 15/2 . (2)
= 175 . 8 + 15
= 1415

3 ½ = 7/2
2 ½ = 5/2

maka
f(x) = 20x^7/2 + 2x^5/2 + 10x
turunan pertama
f'(x) = 20(7/2)x^(7/2 - 1) + 2(5/2)x^(5/2 - 1) + 10
f'(x) = 70x^5/2 + 5x^3/2 + 10
turunan kedua
f"(x) = 70(5/2)x^(5/2 - 1) + 5(3/2)x^(3/2 - 1) + 0
f"(x) = 175x^3/2 + 15/2 x^½

f"(4) = 175(4)^3/2 + 15/2 (4)½
f"(4) = 175 (2²)^3/2 + 15/2 (2²)^½
f"(4) = 175 (2³) + 15/2 (2)
f"(4) = 1.400 + 15
f"(4) = 1.415

Opsi C

semoga berguna +_+