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1 year ago

I need help I’m stuck

Mathematics

1 answer:

marysya [2.9K]1 year ago

6 0

Answer:

3rd one

Step-by-step explanation:

i did it

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Find the angle between u = i+sqr of 7j and v = -i+9j. Round to the nearest tenth of a degree.

Zolol [24]

$\bf ~~~~~~~~~~~~\textit{angle between two vectors } \\\\ cos(\theta)=\cfrac{\stackrel{\textit{dot product}}{u \cdot v}}{\stackrel{\textit{magnitude product}}{||u||~||v||}} \implies \measuredangle \theta = cos^{-1}\left(\cfrac{u \cdot v}{||u||~||v||}\right) \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ \begin{cases} u=i+\sqrt{7}j\implies &\\\\ v=-i+9j\implies & \end{cases} \\\\[-0.35em] ~\dotfill$

$\bf u\cdot v\implies (1)(-1)~+~(\sqrt{7})(9)\implies -1+9\sqrt{7}\implies 9\sqrt{7}-1~\hfill dot~product \\\\[-0.35em] ~\dotfill\\\\ ||u||\implies \sqrt{1^2+(\sqrt{7})^2}\implies \sqrt{1+7}\implies \sqrt{8}~\hfill magnitudes \\\\\\ ||v||\implies \sqrt{(-1)^2+9^2}\implies \sqrt{1+81}\implies \sqrt{82} \\\\[-0.35em] ~\dotfill$

$\bf \theta =cos^{-1}\left( \cfrac{9\sqrt{7}-1}{\sqrt{8}\cdot \sqrt{82}} \right)\implies \theta =cos^{-1}\left( \cfrac{9\sqrt{7}-1}{\sqrt{656}} \right) \\\\\\ \theta \approx cos^{-1}(0.8906496638868531)\implies \theta \approx 27.05$

make sure your calculator is in Degree mode.

6 0

2 years ago

A teacher writes the function f(x)=3x^2-18x+27 on the board. How many times does the graph of the teacher's function intersect t

Oduvanchick [21]

Answer:

Once. at (3,0)

Step-by-step explanation:

It is handy to have a graphing calculator for this kind of question.

Otherwise work it out.

All the terms are multiples of 3, so simplify. $3(x^{2} -6x + 9)$

then factor (x -3)(x-3)

Set each equal to 0 and solve for x.

x - 3 = 0 x = 3

OH ! they are identical! So there is only One value for x that will produce an output of 0.

So it intersects (touches) only once.

7 0

3 years ago

T/2+2=4 two step equations

FromTheMoon [43]

T=4 should be the answer if ur trying 2 solve for T

3 0

2 years ago

Determine weather the following is real or complex <br> i^6-122-7i^2

Leona [35]

Answer:

Real

Step-by-step explanation:

i^6-122-7i^2

(i^2)^3-122-7i^2

(-1)^3-122-7×(-1)

-1-122+7

-123+7

-116

So the final answer is -116

7 0

2 years ago

In Mr. Scott’s class the ratio of boys to girls is 2:3. The total number of students in Mr. Scott’s class is 30. What percent of

Yuri [45]

Answer:

40% of the class is Girls, so 12 students are girls

Step-by-step explanation:

add up the ratio

2+3=5

divide by 5

30/5=6

multipy ratio to find totial number of students

2*6=12

2*3=18

divide the number of students to get the pecentage

12/30=0.4=40%

18/30=0.6=60%

5 0

2 years ago