Can someone answer these 2 questions for me?

Mathematics

1 answer:

Valentin [98]2 years ago

4 0

For the first question x is equal to 4. You get this by adding 7x+2 and 3x and equal it to 42. And then solve algebraically so 10x+2=42
10x=40 so x equals 4
For the second question x is equal to 6.666 and y is equal to 9
You get this by getting x is to 10 as 4 is to 6 and you get y by 6 is to y as 4 is to 6
Hope this helps

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3. The curve C with equation y=f(x) is such that, dy/dx = 3x^2 + 4x +k

Andreas93 [3]

a. Given that y = f(x) and f(0) = -2, by the fundamental theorem of calculus we have

$\displaystyle \frac{dy}{dx} = 3x^2 + 4x + k \implies y = f(0) + \int_0^x (3t^2+4t+k) \, dt$

Evaluate the integral to solve for y :

$\displaystyle y = -2 + \int_0^x (3t^2+4t+k) \, dt$

$\displaystyle y = -2 + (t^3+2t^2+kt)\bigg|_0^x$

$\displaystyle y = x^3+2x^2+kx - 2$

Use the other known value, f(2) = 18, to solve for k :

$18 = 2^3 + 2\times2^2+2k - 2 \implies \boxed{k = 2}$

Then the curve C has equation

$\boxed{y = x^3 + 2x^2 + 2x - 2}$

b. Any tangent to the curve C at a point (a, f(a)) has slope equal to the derivative of y at that point:

$\dfrac{dy}{dx}\bigg|_{x=a} = 3a^2 + 4a + 2$

The slope of the given tangent line $y=x-2$ is 1. Solve for a :

$3a^2 + 4a + 2 = 1 \implies 3a^2 + 4a + 1 = (3a+1)(a+1)=0 \implies a = -\dfrac13 \text{ or }a = -1$

so we know there exists a tangent to C with slope 1. When x = -1/3, we have y = f(-1/3) = -67/27; when x = -1, we have y = f(-1) = -3. This means the tangent line must meet C at either (-1/3, -67/27) or (-1, -3).

Decide which of these points is correct:

$x - 2 = x^3 + 2x^2 + 2x - 2 \implies x^3 + 2x^2 + x = x(x+1)^2=0 \implies x=0 \text{ or } x = -1$

So, the point of contact between the tangent line and C is (-1, -3).

7 0

2 years ago

What are the domain and range of the function? f(x)=−3/5x^3

vichka [17]

<span>
f(x)= −3/5x³</span><span>

The domain is all values x can be. There are no restrictions on x. it can be any real number (-∞ , ∞)

The range is all values y can be. There are noi restrictions on y either because the function is odd. y is </span><span>(-∞ , ∞)

The best answer is D.
domain (-∞, 0] ∪[0, ∞)
range </span><span>(-∞, 0] ∪[0, ∞) </span>

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3 years ago

Austin keeps a right conical basin for the birds in his garden as represented in the diagram. The basin is 40 centimeters deep,

Lina20 [59]

The shortest distance between the tip of the cone and its rim exits 51.11cm.

<h3>What is the shortest distance between the tip of the cone and its rim?</h3>

If you draw a line along the middle of the cone, you'd finish up with two right triangles and the line even bisects the angle between the sloping sides. The shortest distance between the tip of the cone and its rim exists in the hypotenuse of a right triangle with one angle calculating 38.5°. So, utilizing trigonometry and allowing x as the measurement of the shortest distance between the tip of the cone and its rim.

Cos 38.5 = 40 / x

Solving the value of x, we get

Multiply both sides by x

$$\cos \left(38.5^{\circ}\right) x=\frac{40}{x} x$