Find a cubic function with the given zeros.

Mathematics

1 answer:

tester [92]3 years ago

5 0

The cubic function is $f(x)=x^3+3x^2-46x-168$

Option D is correct

Step-by-step explanation:

We need to find the cubic function with the given zeros -6,7,-4

If -6,7,-4 are zeros of the function then:

x=-6, x=7 and x=-4

=> x+6=0,x-7=0 and x+4=0

Multiplying these terms to find the cubic function:

(x+6)(x-7)(x+4)

Solving:

$(x+6)(x-7)(x+4)\\=(x+6)(x(x+4)-7(x+4))\\=(x+6)(x^2+4x-7x-28)\\=(x+6)(x^2-3x-28)\\=x(x^2-3x-28)+6(x^2-3x-28)\\=x^3-3x^2-28x+6x^2-18x-168\\Combining\,\,like\,\,terms:\\=x^3-3x^2+6x^2-28x-18x-168\\=x^3+3x^2-46x-168$

So, the cubic function is $f(x)=x^3+3x^2-46x-168$

Option D is correct

Keywords: cubic function

Learn more about cubic function at:

#learnwithBrainly

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Use the information in the diagram to determine the height of the tree to the nearest foot.

algol13

Answer:

The correct option is A. The height of tree is 60 ft.

Step-by-step explanation:

From the given figure it is noticed that the building is creating a right angle triangle from a point and the tree divides the hypotenuse and base in two equal part.

According to midpoint theorem of triangle: In a triangle, if a line segment connecting the midpoints of two sides, then the line is parallel to third side. The length of line segment is half of the length of third side.

Using midpoint theorem of triangle, we can say that the length of tree is half of the building.

$Tree=\frac{1}{2}\times Building$

$Tree=\frac{1}{2}\times 120$

$Tree=60$

Therefore correct option is A. The height of tree is 60 ft.

5 0

3 years ago

[Will mark as brainliest]

Aleks04 [339]

The answer is: $f^{-1} = 4x^2-3,\quad\text{for } x \leq 0$

The inverse of a function $f(x)$ is another function, $f^{-1}(x)$ , with the following property:

$f(f^{-1}(x)) = f^{-1}(f(x)) = x$

In other words, the inverse of a function does exactly "the opposite" of what the original function does, and so if you compute them both in sequence you return to the starting point.

Think for example to a function that doubles the input, $f(x)=2x$ , and one that halves it: $f(x)= \frac{x}{2}$ . Their composition is clearly the identity function $f(x)=x$ , since you consider "twice the half of something", or "half the double of something".

In general, to invert a function $y=f(x)$ , you have to solve the expression for $x$ , writing an expression like $x = g(y)$ . If you manage to do so, then $g$ is the inverse of $f$ .

In your case, you have

$f(x) = y = -\frac{1}{2}\sqrt{x+3}$

Multiply both sides by $-2$ to get

$-2y = \sqrt{x+3}$

Square both sides to get

$4y^2 = x+3$

Finally, subtract 3 from both sides to get

$x = 4y^2 - 3$

Since the name of the variables doesn't really have a meaning, you can say that the inverse function is

$f^{-1}(x) = 4x^2 - 3$

As for the domain of the inverse function, remember what we said ad the beginning: if the original function goes from set A (domain) to set B (codomain), then the inverse function goes from set B (domain) to set A (codomain). This means that the inverse function is defined on an element in B if and only if that element belongs to the range of the original function, i.e. the set of the elements of the codomain $b \in B$ such that there exists $a \in A : f(a)=b$ . So, we need the range of $f(x)$ .

We know that the range of $g(x)=\sqrt{x}$ is $[0,\infty)$ . When you transform it to $g(x)=\sqrt{x+3}$ you simply translate the graph horizontally, so the range doesn't change. But when you multiply the function times $-\frac{1}{2}$ you affect both extrema of the range, turning it into $(-\infty,0]$ , which you can simply write as $x \leq 0$