What was the value of the third check Tony deposited?

F(x) = 3x + x3

____ [38]

Answer:

Please check the explanation.

Step-by-step explanation:

Given

f(x) = 3x + x³

Taking differentiate

$\frac{d}{dx}\left(3x+x^3\right)$

$\mathrm{Apply\:the\:Sum/Difference\:Rule}:\quad \left(f\pm g\right)'=f\:'\pm g'$

$=\frac{d}{dx}\left(3x\right)+\frac{d}{dx}\left(x^3\right)$

solving

$\frac{d}{dx}\left(3x\right)$

$\mathrm{Take\:the\:constant\:out}:\quad \left(a\cdot f\right)'=a\cdot f\:'$

$=3\frac{d}{dx}\left(x\right)$

$\mathrm{Apply\:the\:common\:derivative}:\quad \frac{d}{dx}\left(x\right)=1$

$=3\cdot \:1$

$=3$

now solving

$\frac{d}{dx}\left(x^3\right)$

$\mathrm{Apply\:the\:Power\:Rule}:\quad \frac{d}{dx}\left(x^a\right)=a\cdot x^{a-1}$

$=3x^{3-1}$

$=3x^2$

Thus, the expression becomes

$\frac{d}{dx}\left(3x+x^3\right)=\frac{d}{dx}\left(3x\right)+\frac{d}{dx}\left(x^3\right)$

$=3+3x^2$

Thus,

f'(x) = 3 + 3x²

Given that f'(x) = 15

substituting the value f'(x) = 15 in f'(x) = 3 + 3x²

f'(x) = 3 + 3x²

15 = 3 + 3x²

switch sides

3 + 3x² = 15

3x² = 15-3

3x² = 12

Divide both sides by 3

x² = 4

$\mathrm{For\:}x^2=f\left(a\right)\mathrm{\:the\:solutions\:are\:}x=\sqrt{f\left(a\right)},\:\:-\sqrt{f\left(a\right)}$

$x=\sqrt{4},\:x=-\sqrt{4}$

$x=2,\:x=-2$

Thus, the value of x will be:

$x=2,\:x=-2$

5 0

3 years ago

If 1/2 is subtracted from four times the reciprocal of a number, the result is 0. Find the number.

Maurinko [17]

Answer:

The Number is 8.

Step-by-step explanation:

Let the number be x.

Given:

1/2 is subtracted from four times the reciprocal of a number, the result is 0.

Hence the equation will become like;

$4\times \frac{1}{x} - \frac{1}{2}=0$

Now Solving the equation we get.

$\frac{4}{x} -\frac{1}{2}=0\\\\\frac{4}{x} = \frac{1}{2}\\\\x= 4\times 2\\x=8$

Now the we can see the number is 8, when 1/2 is subtracted from 4 times the reciprocal of number means 4/8 which becomes 1/2 and hence when 1/2 is subtracted from 1/2 it equals to 0.

Hence the number is 8.

8 0

3 years ago

In an animal shelter, the ratio of cats to dogs is 3 to 5. If there are a total of 120 animals at the shelter, how many cats do

Firdavs [7]

Answer:

B) 45 cats

Step-by-step explanation:

3/(3+5) = 3/8

3/8 of the animals are cats

3/8 × 120

45

6 0

4 years ago

Read 2 more answers

Use the law of cosines to find the value of 2*4*5 cos theta

sweet-ann [11.9K]

We can proceed in solving the problem since all information are given such as 2*4*5costheta.
we have a=4, b=5, and C=theta
let us solve for "c" using Pythagorean
c²=a²+b²
c²=4²+5²
c=6.4
Solving for theta or C
c²=a²+b²-2abcosC
6.4²=4²+5²-2*4*5*cosC
C=90

3 0

3 years ago

Read 2 more answers

35 is less than half a number equals 14. What is the number?<br> Plz help

Nady [450]

Hey there!

Let's write this as an equation, with n representing the unknown number.

0.5n-35=14

First, we add 35 to both sides.

0.5n=49

We divide both sides by 0.5.

n=108

Therefore, your number is 108

I hope this helps!

7 0

3 years ago