I don't speak Romanian, but the closest translation for this suggests you're trying to compute

Integrate by parts:

where
u = ln(x)² ⇒ du = 2 ln(x)/x dx
dv = x³ dx ⇒ v = 1/4 x⁴

Integrate by parts again:

where
u' = ln(x) ⇒ du' = dx/x
dv' = x³ dx ⇒ v' = 1/4 x⁴

So, we have





A central angle means an angle that is at the center of a circle and whose legs are intersecting the circle.
<h3>What is a central angle?</h3>
Your information is incomplete as the data is not given. Therefore, an overview will be given.
Central angles are shaped by an arc between the two points. When a central angle and the inscribed angle intercept the same arc, then the central angle would be the double of the inscribed angles while the inscribed angle will be half of the central angle.
Learn more about central angle on:
brainly.com/question/19758686
Answer:
The length of BC is 17
Step-by-step explanation:
When we construct a triangle with the data, we will end up a isosceles triangle.
In a isosceles triangle , we know that tow angles and two sides are equal
The questions states that

Then sides AC and AB are also equal
On equation their values
2X - 8 = X+9
2X = X + 9 +8
2X = X + 17
2X - X = 17
X = 17
The length of BC = X = 17
Sixty-three, 60 + 3, 9 x 7, 63