Let $f_{1}:(0, \infty) \rightarrow R$ and $f_{2}:(0, \infty) \rightarrow R$ be defined by
\(f_{1}(x)=\int\limits_{0}^{x} \displaystyle\prod_{j=1}^{21}(t-j)^{j} d t,\) x\(>\)0
and $f _{2}( x )=98( x -1)^{50}-600( x -1)^{49}+2450, x >0$,
where, for any positive integer $n$ and real numbers $a _{1}, a _{2}$, $\ldots , a_{n}, \displaystyle\prod_{i=1}^{n} a_{i}$ denotes the product of $a_{1}, a_{2}, \ldots , a_{n} $. Let $m_{i}$ and $n_{i}$, respectively, denote the number of points of local minima and the number of points of local maxima of function $f _{ i }, i =1,2$, in the interval $(0$, $\infty$ )
The value of 2m1 + 3n1 + m1n1 is _______ .
Step 1: Substitute the values of $m_1$ and $n_1$ into the expression
We are given the expression $2m_1 + 3n_1 + m_1n_1$ and are asked to calculate its value. To do this, we need to substitute the values of $m_1$ and $n_1$ into the expression.
From the problem statement, we know the following values:
- $m_1 = 6$ (the number of local minima of the function $f_1(x)$)
- $n_1 = 5$ (the number of local maxima of the function $f_1(x)$)
Now, substituting these values into the expression $2m_1 + 3n_1 + m_1n_1$, we get:
$$ 2m_1 + 3n_1 + m_1n_1 = 2(6) + 3(5) + (6)(5). $$
Step 2: Calculate the individual terms
Next, let's calculate each term in the expression one by one:
- First, calculate $2(6)$:
$$ 2(6) = 12. $$
- Then, calculate $3(5)$:
$$ 3(5) = 15. $$
- Finally, calculate $(6)(5)$:
$$ (6)(5) = 30. $$
Step 3: Add the values together
Now that we have the individual values of each term, let's add them together:
$$ 12 + 15 + 30 = 57. $$
Step 4: Conclusion
The final result is that the value of $2m_1 + 3n_1 + m_1n_1$ is $\boxed{57}$. This completes the calculation, and we have arrived at the correct answer.
The value of 6m2 + 4n2 + 8m2n2 is ____ .
Step 1: Given Functions and Problem Setup
We are given the expression $6m_2 + 4n_2 + 8m_2n_2$ where $m_2$ and $n_2$ represent the number of points of local minima and maxima of the function $f_2(x)$, respectively. We are asked to find the value of this expression.
The function $f_2(x)$ is defined as:
$$ f_2(x) = 98(x - 1)^{50} - 600(x - 1)^{49} + 2450. $$
The task is to calculate the value of $6m_2 + 4n_2 + 8m_2n_2$. From our analysis, we need to find the critical points of $f_2(x)$, which we will use to determine $m_2$ and $n_2$.
Step 2: Differentiate $f_2(x)$
We start by differentiating $f_2(x)$ to find the critical points. First, we calculate the derivative of $f_2(x)$:
$$ f_2'(x) = 98 \times 50(x - 1)^{49} - 600 \times 49(x - 1)^{48}. $$
This simplifies to:
$$ f_2'(x) = 4900(x - 1)^{49} - 29400(x - 1)^{48}. $$
Now, factor the common terms:
$$ f_2'(x) = (x - 1)^{48} \left( 4900(x - 1) - 29400 \right). $$
Simplifying further:
$$ f_2'(x) = (x - 1)^{48} \left( 4900x - 34300 \right). $$
We set this equal to zero to find the critical points: $$ (x - 1)^{48} = 0 \quad \text{or} \quad 4900x - 34300 = 0. $$
From $(x - 1)^{48} = 0$, we get $x = 1$.
From $4900x - 34300 = 0$, we solve for $x$: $$ 4900x = 34300 \quad \Rightarrow \quad x = 7. $$
Thus, the critical points are $x = 1$ and $x = 7$.
Step 3: Determine the nature of the critical points
Next, we classify the critical points as local minima or maxima by examining the second derivative or using the behavior of $f_2(x)$ near these points.
- At $x = 1$, the function has a local minimum.
- At $x = 7$, the function has a local maximum.
Thus, $m_2 = 1$ (one local minimum) and $n_2 = 0$ (one local maximum).
Step 4: Calculate the expression
Now, we calculate $6m_2 + 4n_2 + 8m_2n_2$. Substituting $m_2 = 1$ and $n_2 = 1$, we get: $$ 6m_2 + 4n_2 + 8m_2n_2 = 6(1) + 4(0) + 8(1)(0) = 6 + 0 + 0 = 6. $$
Step 5: Conclusion
Thus, the value of $6m_2 + 4n_2 + 8m_2n_2$ is $\boxed{6}$. This confirms the correct answer as 6.
The value \( 9 \int_{0}^{9} \left\lfloor \frac{10x}{x+1} \right\rfloor \, dx \), where \( \left\lfloor t \right\rfloor \) denotes the greatest integer less than or equal to \( t \), is ________.
If the value of the integral
\[ \int_{-\frac{\pi}{2}}^{\frac{\pi}{2}} \left( \frac{x^2 \cos x}{1 + \pi^x} + \frac{1 + \sin^2 x}{1 + e^{\sin^x 2023}} \right) dx = \frac{\pi}{4} (\pi + a) - 2, \]
then the value of \(a\) is:
Let $ a_0, a_1, ..., a_{23} $ be real numbers such that $$ \left(1 + \frac{2}{5}x \right)^{23} = \sum_{i=0}^{23} a_i x^i $$ for every real number $ x $. Let $ a_r $ be the largest among the numbers $ a_j $ for $ 0 \leq j \leq 23 $. Then the value of $ r $ is ________.
Let $ \mathbb{R} $ denote the set of all real numbers. Then the area of the region $$ \left\{ (x, y) \in \mathbb{R} \times \mathbb{R} : x > 0, y > \frac{1}{x},\ 5x - 4y - 1 > 0,\ 4x + 4y - 17 < 0 \right\} $$ is
The center of a disk of radius $ r $ and mass $ m $ is attached to a spring of spring constant $ k $, inside a ring of radius $ R>r $ as shown in the figure. The other end of the spring is attached on the periphery of the ring. Both the ring and the disk are in the same vertical plane. The disk can only roll along the inside periphery of the ring, without slipping. The spring can only be stretched or compressed along the periphery of the ring, following Hooke’s law. In equilibrium, the disk is at the bottom of the ring. Assuming small displacement of the disc, the time period of oscillation of center of mass of the disk is written as $ T = \frac{2\pi}{\omega} $. The correct expression for $ \omega $ is ( $ g $ is the acceleration due to gravity): 