All categories

2 years ago

Please help and show all work!

Mathematics

1 answer:

Soloha48 [4]2 years ago

3 0

2 is Reflexive property
4 is (I don't remember the specific property of this)

You might be interested in

Math question #1 please show steps

-Dominant- [34]

Answer:

Step-by-step explanation:

An approximation of an integral is given by:

$\displaystyle \int_a^bf(x)\, dx\approx \sum_{k=1}^nf(x_k)\Delta x\text{ where } \Delta x=\frac{b-a}{n}$

First, find Δx. Our a = 2 and b = 8:

$\displaystyle \Delta x=\frac{8-2}{n}=\frac{6}{n}$

The left endpoint is modeled with:

$x_k=a+\Delta x(k-1)$

And the right endpoint is modeled with:

$x_k=a+\Delta xk$

Since we are using a Left Riemann Sum, we will use the first equation.

Our function is:

$f(x)=\cos(x^2)$

Therefore:

$f(x_k)=\cos((a+\Delta x(k-1))^2)$

By substitution:

$\displaystyle f(x_k)=\cos((2+\frac{6}{n}(k-1))^2)$

Putting it all together:

$\displaystyle \int_2^8\cos(x^2)\, dx\approx \sum_{k=1}^{n}\Big(\cos((2+\frac{6}{n}(k-1))^2)\Big)\frac{6}{n}$

Thus, our answer is C.

*Note: Not sure why they placed the exponent outside the cosine. Perhaps it was a typo. But C will most likely be the correct answer regardless.

5 0

2 years ago

13....................

Mashcka [7]

13.

(a)

$y=-5x^2+21x-3$

for x = 2:

$y=-5(2)^2+21(2)-3=-20+42-3=19$

for x = 5

$y=-5(5)^2+21(5)-3=-125+105-3=-23$

(b)

The graph is:

(c)

Using the graph:

$\begin{gathered} x=1.8,y=18.6 \\ x=0.548,y=7 \\ x=3.65,y=7 \end{gathered}$ $\begin{gathered} x=1.8 \\ y=-5(1.8)^2+21(1.8)-3=-16.2+37.8-3=18.6 \end{gathered}$ $\begin{gathered} y=7 \\ -5x^2+21x-3=7 \\ -5x^2+21x-10=0 \end{gathered}$

Using the quadratic formula:

$\begin{gathered} x=\frac{-b\pm\sqrt[]{b^2-4ac}}{2a} \\ x=\frac{-21\pm\sqrt[]{21^2-4(-5)(-10)}}{2(-5)} \\ x=\frac{-21\pm\sqrt[]{241}}{-10} \\ x=0.54758 \\ or \\ x=3.6524 \end{gathered}$