Answer:
following are the solution to the given points:
Step-by-step explanation:
In point a:
![\vec{v} = -\vec{1 i} +\vec{1j}\\\\|\vec{v}| = \sqrt{-1^2+1^2}](https://tex.z-dn.net/?f=%5Cvec%7Bv%7D%20%3D%20-%5Cvec%7B1%20i%7D%20%2B%5Cvec%7B1j%7D%5C%5C%5C%5C%7C%5Cvec%7Bv%7D%7C%20%3D%20%5Csqrt%7B-1%5E2%2B1%5E2%7D)
![=\sqrt{1+1}\\\\=\sqrt{2}](https://tex.z-dn.net/?f=%3D%5Csqrt%7B1%2B1%7D%5C%5C%5C%5C%3D%5Csqrt%7B2%7D)
calculating unit vector:
![\frac{\vec{v}}{|\vec{v}|} = \frac{-1i+1j}{\sqrt{2}}](https://tex.z-dn.net/?f=%5Cfrac%7B%5Cvec%7Bv%7D%7D%7B%7C%5Cvec%7Bv%7D%7C%7D%20%3D%20%5Cfrac%7B-1i%2B1j%7D%7B%5Csqrt%7B2%7D%7D)
the point Q is at a distance h from P(6,6) Here, h=0.1
![a=-6+O.1 \times \frac{-1}{\sqrt{2}}\\\\= 5.92928 \\\\b= 6+O.1 \times \frac{-1}{\sqrt{2}} \\\\= 6.07071](https://tex.z-dn.net/?f=a%3D-6%2BO.1%20%5Ctimes%20%5Cfrac%7B-1%7D%7B%5Csqrt%7B2%7D%7D%5C%5C%5C%5C%3D%205.92928%20%5C%5C%5C%5Cb%3D%206%2BO.1%20%5Ctimes%20%5Cfrac%7B-1%7D%7B%5Csqrt%7B2%7D%7D%20%5C%5C%5C%5C%3D%206.07071)
the value of Q= (5.92928 ,6.07071 )
In point b:
Calculating the directional derivative of
at P in the direction of ![\vec{v}](https://tex.z-dn.net/?f=%5Cvec%7Bv%7D)
![f_{PQ} (P) =\fracx{f(Q)-f(P)}{h}\\\\](https://tex.z-dn.net/?f=f_%7BPQ%7D%20%28P%29%20%3D%5Cfracx%7Bf%28Q%29-f%28P%29%7D%7Bh%7D%5C%5C%5C%5C)
![=\frac{f(5.92928 ,6.07071)-f(6,6)}{0.1}\\\\=\frac{\sqrt{(5.92928+ 3 \times 6.07071)}-\sqrt{(6+ 3\times 6)}}{0.1}\\\\= \frac{0.197651557}{0.1}\\\\= 1.97651557](https://tex.z-dn.net/?f=%3D%5Cfrac%7Bf%285.92928%20%2C6.07071%29-f%286%2C6%29%7D%7B0.1%7D%5C%5C%5C%5C%3D%5Cfrac%7B%5Csqrt%7B%285.92928%2B%203%20%5Ctimes%206.07071%29%7D-%5Csqrt%7B%286%2B%203%5Ctimes%206%29%7D%7D%7B0.1%7D%5C%5C%5C%5C%3D%20%5Cfrac%7B0.197651557%7D%7B0.1%7D%5C%5C%5C%5C%3D%201.97651557)
![\vec{v} = 1.97651557](https://tex.z-dn.net/?f=%5Cvec%7Bv%7D%20%3D%201.97651557)
In point C:
Computing the directional derivative using the partial derivatives of f.
![f_x(x,y)= \frac{1}{2 \sqrt{x+3y}}\\\\ f_x (6,6)= \frac{1}{2 \sqrt{22}}\\\\f_x(x,y)= \frac{1}{\sqrt{x+3y}}\\\\ f_x (6,6)= \frac{1}{\sqrt{22}}\\\\f_{(PQ)}(P)= (f_x \vec{i} + f_y \vec{j}) \cdot \frac{\vec{v}}{|\vec{v}|}\\\\= (\frac{1}{2 \sqrt{22}}\vec{i} + \frac{1}{\sqrt{22}} \vec{j}) \cdot \frac{-1}{\sqrt{2}}\vec{i} + \frac{1}{\sqrt{2}} \vec{j}](https://tex.z-dn.net/?f=f_x%28x%2Cy%29%3D%20%5Cfrac%7B1%7D%7B2%20%5Csqrt%7Bx%2B3y%7D%7D%5C%5C%5C%5C%20f_x%20%286%2C6%29%3D%20%5Cfrac%7B1%7D%7B2%20%5Csqrt%7B22%7D%7D%5C%5C%5C%5Cf_x%28x%2Cy%29%3D%20%5Cfrac%7B1%7D%7B%5Csqrt%7Bx%2B3y%7D%7D%5C%5C%5C%5C%20f_x%20%286%2C6%29%3D%20%5Cfrac%7B1%7D%7B%5Csqrt%7B22%7D%7D%5C%5C%5C%5Cf_%7B%28PQ%29%7D%28P%29%3D%20%28f_x%20%5Cvec%7Bi%7D%20%2B%20f_y%20%5Cvec%7Bj%7D%29%20%5Ccdot%20%5Cfrac%7B%5Cvec%7Bv%7D%7D%7B%7C%5Cvec%7Bv%7D%7C%7D%5C%5C%5C%5C%3D%20%28%5Cfrac%7B1%7D%7B2%20%5Csqrt%7B22%7D%7D%5Cvec%7Bi%7D%20%2B%20%5Cfrac%7B1%7D%7B%5Csqrt%7B22%7D%7D%20%5Cvec%7Bj%7D%29%20%5Ccdot%20%20%20%5Cfrac%7B-1%7D%7B%5Csqrt%7B2%7D%7D%5Cvec%7Bi%7D%20%2B%20%5Cfrac%7B1%7D%7B%5Csqrt%7B2%7D%7D%20%5Cvec%7Bj%7D)
For this case we have the following equation:
r = 9 sin (θ)
In addition, we have the following change of variables:
y = r * sine (θ)
Rewriting the equation we have:
r = 9 sin (θ)
r = 9 (y / r)
r ^ 2 = 9y
On the other hand:
r ^ 2 = x ^ 2 + y ^ 2
Substituting values:
x ^ 2 + y ^ 2 = 9y
Rewriting:
x ^ 2 + y ^ 2 - 9y = 0
Completing squares:
x ^ 2 + y ^ 2 - 9y + (-9/2) ^ 2 = (-9/2) ^ 2
Rewriting:
x ^ 2 + 1/4 (2y-9) ^ 2 = 81/4
4x ^ 2 + (2y-9) ^ 2 = 81
Answer:
The Cartesian equation is:
4x ^ 2 + (2y-9) ^ 2 = 81
Answer:
13 pencils.
Step-by-step explanation:
Let x be the pens and y be the pencils
Given:
Brian purchased pens for 75 cents each and pencils for 40 cents each he bought total of 22 writing utensils for $11.95.
Total pens and pencils is 22
So,
----------------(1)
And he bought all utensils for $11.95. and each pen for 75 cents and pencils for 40 cents.
------------(2)
solve equation 1 and equation 2 for x and y.
From equation 1.
![x+y=22](https://tex.z-dn.net/?f=x%2By%3D22)
----------------(3)
put y value in equation 2.
![0.75x+0.4(22-x)=11.95](https://tex.z-dn.net/?f=0.75x%2B0.4%2822-x%29%3D11.95)
![0.75x+0.4\times 22-0.4x=11.95](https://tex.z-dn.net/?f=0.75x%2B0.4%5Ctimes%2022-0.4x%3D11.95)
![0.75x+8.8-0.4x=11.95](https://tex.z-dn.net/?f=0.75x%2B8.8-0.4x%3D11.95)
![0.75x-0.4x=11.95-8.8](https://tex.z-dn.net/?f=0.75x-0.4x%3D11.95-8.8)
![0.35x=3.15](https://tex.z-dn.net/?f=0.35x%3D3.15)
![x=\frac{3.15}{0.35}](https://tex.z-dn.net/?f=x%3D%5Cfrac%7B3.15%7D%7B0.35%7D)
![x=9](https://tex.z-dn.net/?f=x%3D9)
Now substitute x value in equation 3.
![y=22-9](https://tex.z-dn.net/?f=y%3D22-9)
![y=13](https://tex.z-dn.net/?f=y%3D13)
So, he buy 13 pencils.
Answer:
Not equivalent
Step-by-step explanation:
The three would also be distributed to z making the correct equivalent expression 15+3z