Can someone please help?!

What's 2+2 ? I have a hard time understanding what's the answer

Anarel [89]

Answer:

4

Step-by-step explanation:

3 0

3 years ago

Read 2 more answers

Find the domain over which the function y = x + 6x is monotonic increasing.

iragen [17]

Answer:

x > -3

$\sf (-3, \infty)$

Step-by-step explanation:

Domain: input values (x-values)

Monotonic increasing: always increasing.
A function is increasing when its graph rises from left to right.

The graph of a quadratic function is a parabola. If the leading term is positive, the parabola opens upwards. The domain over which the function is increasing for a parabola that opens upwards is values greater than the x-value of the vertex.

Vertex

Standard form of quadratic equation: $\sf y=ax^2+bx+c$

$\textsf{x-value of vertex}=\sf -\dfrac{b}{2a}$

Given function:

$\sf y=x^2+6x$

Therefore, x-value of function's vertex:

$\sf \implies x= -\dfrac{6}{2}=-3$

Final Solution

The function is increasing when x > -3

$\sf (-3, \infty)$

4 0

2 years ago

Hi need help for this maths question

Sauron [17]

a) If f(y) is a probability density function, then both f(y) ≥ 0 for all y in its support, and the integral of f(y) over its entire support should be 1. eˣ > 0 for all real x, so the first condition is met. We have

$\displaystyle \int_{-\infty}^\infty f(y) \, dy = \frac14 \int_0^\infty e^{-\frac y4} \, dy = -\left(\lim_{y\to\infty}e^{-\frac y4} - e^0\right) = \boxed{1}$

so both conditions are met and f(y) is indeed a PDF.

b) The probability P(Y > 4) is given by the integral,

$\displaystyle \int_{-\infty}^4 f(y) \, dy = \frac14 \int_0^4 e^{-\frac y4} \, dy = -\left(e^{-1} - e^0\right) = \frac{e - 1}{e} \approx \boxed{0.632}$

c) The mean is given by the integral,

$\displaystyle \int_{-\infty}^\infty y f(y) \, dy = \frac14 \int_0^\infty y e^{-\frac y4} \, dy$

Integrate by parts, with

$u = y \implies du = dy$

$dv = e^{-\frac y4} \, dy \implies v = -4 e^{-\frac y4}$

Then

$\displaystyle \int_{-\infty}^\infty y f(y) \, dy = \frac14 \left(\left(\lim_{y\to\infty}\left(-4y e^{-\frac y4}\right) - \left(-4\cdot0\cdot e^0\right)\right) + 4 \int_0^\infty e^{-\frac y4} \, dy\right)$

$\displaystyle \cdots = \int_0^\infty e^{-\frac y4} \, dy$

$\displaystyle \cdots = -4 \left(\lim_{y\to\infty} e^{-\frac y4} - e^0\right) = \boxed{4}$

8 0

2 years ago

Dave found that about 8/9 of the students in his class have a cell phone.What percent of the students in his class do NOT HAVE a

iris [78.8K]

If the number of students in the class is considered to be 1, and 8/9 of the students have a cell phone, the fraction indicating the number of students who do not have a cell phone is:
1- 8/9= 1/9.

1/9 of the students don't have a cell phone~

6 0

2 years ago

Two cars traveled equal distances in different amounts of time. Car A traveled the distance in 2h, and Car B traveled the distan

mote1985 [20]

Let the speed of car B be x.
Car B is faster than car A 15mph so the speed of car A would be: x-15.
From the problem, we could come up with an equation:
$2(x - 15) = 1.5x \\ x = 60$
So car B was traveling at 60mph

4 0

3 years ago