jika (a,b) adalah titik minimum grafik fungsi f(x)=7-√25-x² maka nilai a²+b²=… a. 4 b. 5 c. 8 d.10 e.13

Nilai minimum

f (x ) = 7 - √(25- x²) = 7 - (25 - x²)¹/²
 f' (x)= 0 -->  - ¹/₂ (25- x²) ⁻¹/² .(-2x) = 0
-x (25 - x²)⁻¹/²  = 0
- x/ √(25- x²) = 0 --> x = 0

f(0) = 7 - √(25-x²)
f(0)= 7 - √(25-0) --> f(0)= 7 - 5 = 2
(a,b) = (0, 2)
a² + b² = 0²+2²  = 4