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3 years ago

Is -15.51+ 8.55 positive or negative

Mathematics

1 answer:

kherson [118]3 years ago

4 0

Answer:

negative

Step-by-step explanation:

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PLEASE HELP FAST..WILL MARK AS BRAINLIEST IF GIVEN GOOD ANSWER

Elodia [21]

Answer:

obtuse angles and right angle

7 0

3 years ago

A square matrix A is said to be idempotent iff A2 = A. (i) Show that if A is idempotent, then so is I − A. (ii) Show that if A i

muminat

Answer:

Step-by-step explanation:

Given that A is a square matrix and A is idempotent

$A^2 = A$

Consider I-A

i) $(I-A)^2 = (I-A).(I-A)\\= I^2 -2A.I+A^2\\= I-2A+A\\=I-A$

It follows that I-A is also idempotent

ii) Consider the matrix 2A-I

$(2A-I).(2A-I)=\\4A^2-4AI+I^2\\= 4A-4A+I\\=I$

So it follows that 2A-I matrix is its own inverse.

7 0

3 years ago

Esteban paid $134.10 for 4½ sheets of plywood at the local home improvement store. What does one sheet of plywood cost? A. $28.9

Yakvenalex [24]

Answer:$29.80

Step-by-step explanation:Esteban paid $134.10 for 4½ sheets of plywood at the local home improvement store. What does one sheet of plywood cost? A. $33.53 B. $28.90 C. $29.80 D. $29.78

Esteban paid $134.10 for 4½ sheets of plywood at the local home improvement store. One sheet of plywood costs 134.10/4.5 = $29.80.

5 0

3 years ago

For the function f defined below, what is the value of f(-1)? fx=x+3<br> -----<br> 2

Pepsi [2]

Answer:

6) C 1

7) A 3 (im not sure for this one because it's blurry)

8) C 1

Step-by-step explanation:

6) Replace the f(x) for -1 since we are told f(x) = -1. We then need to use the inverse operation to get x by itself.

$- 1 = \frac{x - 3}{ 2}$

Since the opposite of division (which is indicated by the fraction line) is multiplication, we need to multiply the number on the left (-1) times 2.

$- 2 = x - 3$

For this step, the opposite of subtraction is addition so in this step, we must add 3 to -2.

$1 = x$

7) Can't explain cause I'm not sure if I'm right

8) To find out the slope of two coordinates we must use the following to determine it.

<h3>(IN THE PICTURE ATTACHED)</h3>

In this case, the y with the little two will be 4 and the y with the little one is 1. 4-1 is 3 and that's the y cooridnate sorted

For the x coordinate, the x with the little two is 1 and the x with the little one is -2. Thus, we must solve 1-(-2) which also equals 3.

<h3>Since the final coordinates are 3/3 and it simplifies, the final answer is 1.</h3>

6 0

2 years ago

99 POINT QUESTION, PLUS BRAINLIEST!!!

VladimirAG [237]

First, we have to convert our function (of x) into a function of y (we revolve the curve around the y-axis). So:

$y=100-x^2\\\\x^2=100-y\qquad\bold{(1)}\\\\\boxed{x=\sqrt{100-y}}\qquad\bold{(2)} \\\\\\0\leq x\leq10\\\\y=100-0^2=100\qquad\wedge\qquad y=100-10^2=100-100=0\\\\\boxed{0\leq y\leq100}$

And the derivative of x:

$x'=\left(\sqrt{100-y}\right)'=\Big((100-y)^\frac{1}{2}\Big)'=\dfrac{1}{2}(100-y)^{-\frac{1}{2}}\cdot(100-y)'=\\\\\\=\dfrac{1}{2\sqrt{100-y}}\cdot(-1)=\boxed{-\dfrac{1}{2\sqrt{100-y}}}\qquad\bold{(3)}$

Now, we can calculate the area of the surface:

$A=2\pi\int\limits_0^{100}\sqrt{100-y}\sqrt{1+\left(-\dfrac{1}{2\sqrt{100-y}}\right)^2}\,\,dy=\\\\\\= 2\pi\int\limits_0^{100}\sqrt{100-y}\sqrt{1+\dfrac{1}{4(100-y)}}\,\,dy=(\star)$

We could calculate this integral (not very hard, but long), or use (1), (2) and (3) to get:

$(\star)=2\pi\int\limits_0^{100}1\cdot\sqrt{100-y}\sqrt{1+\dfrac{1}{4(100-y)}}\,\,dy=\left|\begin{array}{c}1=\dfrac{-2\sqrt{100-y}}{-2\sqrt{100-y}}\end{array}\right|= \\\\\\= 2\pi\int\limits_0^{100}\dfrac{-2\sqrt{100-y}}{-2\sqrt{100-y}}\cdot\sqrt{100-y}\cdot\sqrt{1+\dfrac{1}{4(100-y)}}\,\,dy=\\\\\\ 2\pi\int\limits_0^{100}-2\sqrt{100-y}\cdot\sqrt{100-y}\cdot\sqrt{1+\dfrac{1}{4(100-y)}}\cdot\dfrac{dy}{-2\sqrt{100-y}}=\\\\\\$

$=2\pi\int\limits_0^{100}-2\big(100-y\big)\cdot\sqrt{1+\dfrac{1}{4(100-y)}}\cdot\left(-\dfrac{1}{2\sqrt{100-y}}\, dy\right)\stackrel{\bold{(1)}\bold{(2)}\bold{(3)}}{=}\\\\\\= \left|\begin{array}{c}x=\sqrt{100-y}\\\\x^2=100-y\\\\dx=-\dfrac{1}{2\sqrt{100-y}}\, \,dy\\\\a=0\implies a'=\sqrt{100-0}=10\\\\b=100\implies b'=\sqrt{100-100}=0\end{array}\right|=\\\\\\= 2\pi\int\limits_{10}^0-2x^2\cdot\sqrt{1+\dfrac{1}{4x^2}}\,\,dx=(\text{swap limits})=\\\\\\$

$=2\pi\int\limits_0^{10}2x^2\cdot\sqrt{1+\dfrac{1}{4x^2}}\,\,dx= 4\pi\int\limits_0^{10}\sqrt{x^4}\cdot\sqrt{1+\dfrac{1}{4x^2}}\,\,dx=\\\\\\= 4\pi\int\limits_0^{10}\sqrt{x^4+\dfrac{x^4}{4x^2}}\,\,dx= 4\pi\int\limits_0^{10}\sqrt{x^4+\dfrac{x^2}{4}}\,\,dx=\\\\\\= 4\pi\int\limits_0^{10}\sqrt{\dfrac{x^2}{4}\left(4x^2+1\right)}\,\,dx= 4\pi\int\limits_0^{10}\dfrac{x}{2}\sqrt{4x^2+1}\,\,dx=\\\\\\=\boxed{2\pi\int\limits_0^{10}x\sqrt{4x^2+1}\,dx}$

Calculate indefinite integral:

$\int x\sqrt{4x^2+1}\,dx=\int\sqrt{4x^2+1}\cdot x\,dx=\left|\begin{array}{c}t=4x^2+1\\\\dt=8x\,dx\\\\\dfrac{dt}{8}=x\,dx\end{array}\right|=\int\sqrt{t}\cdot\dfrac{dt}{8}=\\\\\\=\dfrac{1}{8}\int t^\frac{1}{2}\,dt=\dfrac{1}{8}\cdot\dfrac{t^{\frac{1}{2}+1}}{\frac{1}{2}+1}=\dfrac{1}{8}\cdot\dfrac{t^\frac{3}{2}}{\frac{3}{2}}=\dfrac{2}{8\cdot3}\cdot t^\frac{3}{2}=\boxed{\dfrac{1}{12}\left(4x^2+1\right)^\frac{3}{2}}$

And the area:

$A=2\pi\int\limits_0^{10}x\sqrt{4x^2+1}\,dx=2\pi\cdot\dfrac{1}{12}\bigg[\left(4x^2+1\right)^\frac{3}{2}\bigg]_0^{10}=\\\\\\= \dfrac{\pi}{6}\left[\big(4\cdot10^2+1\big)^\frac{3}{2}-\big(4\cdot0^2+1\big)^\frac{3}{2}\right]=\dfrac{\pi}{6}\Big(\big401^\frac{3}{2}-1^\frac{3}{2}\Big)=\boxed{\dfrac{401^\frac{3}{2}-1}{6}\pi}$

Answer D.

6 0

3 years ago

Read 2 more answers

Is -15.51+ 8.55 positive or negative​

Is -15.51+ 8.55 positive or negative