All categories

3 years ago

Can you help me please thank you

Mathematics

1 answer:

poizon [28]3 years ago

3 0

Answer:

-3ab, -9x^2 -13x

Step-by-step explanation:

45a^4b^3 - 90a^3b/ 15a^2b

-45ab^2/15a^2b

-3ab

13) (x-7x^2) - (2x^2+14x)

-9x^2 -13x

You might be interested in

Which point is the image of P

riadik2000 [5.3K]

Answer:

Step-by-step explanation:

we know that xoy is 90° on every quadrant

also the origine where p start is a little bit down from x axis so A is the right answer as it is the most logical point

D and C cant be P because are a very large angle of rotation than 105.B is smaller then 105 rotation of p so A is the right one.

3 0

3 years ago

For the differential equation dy/dt=ky, k is a constant, y(0)=24, and y(1)=18. What is the value of k?

Gre4nikov [31]

The equation is separable, so solving it is trivial:

$\dfrac{\mathrm dy}{\mathrm dt}=ky\implies\dfrac{\mathrm dy}y=k\,\mathrm dt$

Integrating both sides gives

$\ln|y|=kt+C\implies y=e^{kt+C}=Ce^{kt}$

Given $y(0)=24$ and $y(1)=18$ , we find

$24=C$

$18=Ce^k=24e^k\implies e^k=\dfrac34\implies k=ln\dfrac34$

so the answer is E.

8 0

4 years ago

Read 2 more answers

rob has a page with 25 stickers. he bought 13 of the stickers his mom bought him the rest of the stickers how many stickers did

posledela

25 -13 = 12
His mom bought 12 stickers.

5 0

3 years ago

Read 2 more answers

Evaluate the following integral (Calculus 2) Please show step by step explanation!

Nuetrik [128]

Answer:

$4\ln \left| \dfrac{1}{3}\sqrt{9+(\ln x)^2} + \dfrac{1}{3}\ln x \right|+\text{C}$

Step-by-step explanation:

Fundamental Theorem of Calculus

$\displaystyle \int \text{f}(x)\:\text{d}x=\text{F}(x)+\text{C} \iff \text{f}(x)=\dfrac{\text{d}}{\text{d}x}(\text{F}(x))$

If differentiating takes you from one function to another, then integrating the second function will take you back to the first with a constant of integration.

Given indefinite integral:

$\displaystyle \int \dfrac{4}{x\sqrt{9+(\ln(x))^2}}\:\:\text{d}x$

Rewrite 9 as 3²:

$\implies \displaystyle \int \dfrac{4}{x\sqrt{3^2+(\ln(x))^2}}\:\:\text{d}x$

Integration by substitution

$\boxed{\textsf{For }\sqrt{a^2+x^2} \textsf{ use the substitution }x=a \tan\theta}$

$\textsf{Let } \ln x=3 \tan \theta$

$\begin{aligned}\implies \sqrt{3^2+(\ln x)^2} & =\sqrt{3^2+(3 \tan\theta)^2}\\ & = \sqrt{9+9\tan^2 \theta}\\ & = \sqrt{9(1+\tan^2 \theta)}\\ & = \sqrt{9\sec^2 \theta}\\ & = 3 \sec\theta\end{aligned}$

Find the derivative of ln x and rewrite it so that dx is on its own:

$\implies \ln x=3 \tan \theta$

$\implies \dfrac{1}{x}\dfrac{\text{d}x}{\text{d}\theta}=3 \sec^2\theta$

$\implies \text{d}x=3x \sec^2\theta\:\:\text{d}\theta$

Substitute everything into the original integral:

$\begin{aligned} \implies \displaystyle \int \dfrac{4}{x\sqrt{9+(\ln(x))^2}}\:\:\text{d}x & = \int \dfrac{4}{3x \sec \theta} \cdot 3x \sec^2\theta\:\:\text{d}\theta\\\\ & = \int 4 \sec \theta \:\: \text{d}\theta\end{aligned}$

Take out the constant:

$\implies \displaystyle 4 \int \sec \theta\:\:\text{d}\theta$

$\boxed{\begin{minipage}{7 cm}\underline{Integrating $\sec kx$}\\\\$\displaystyle \int \sec kx\:\text{d}x=\dfrac{1}{k} \ln \left| \sec kx + \tan kx \right|\:\:(+\text{C})$\end{minipage}}$