All categories

3 years ago

HELP FAST PLEASE!!!!!

Mathematics

1 answer:

lidiya [134]3 years ago

3 0

Alright, lets get started.

The answer Sandra got is correct that is zero but there are some mistakes she made while writing steps.

$2 cot(\frac{-9\pi}{2}) = 2 cot(\frac{9\pi}{2})$ Incorrect step

Because as per even/odd identity,

Cot (-Θ) = - cot (Θ)

Hence

$2 cot (\frac{-9\pi}{2}) = - 2 cot (\frac{9\pi}{2})$

Now,

It could be written as

$-2 cot (\frac{9\pi}{2}) = -2 cot (\frac{\pi}{2})$

$-2 * 0$

Hence the answer is 0. : Answer

Hope it will help :)

You might be interested in

Trigonometry help?? Thank you so much!!

liq [111]

Answer:

7) a = 60; b = 100

8) c = 20

9) d = 45

Step-by-step explanation:

a + 120 = 180

a = 60

b + 80 = 180

b = 100

5c + 4c = 180

9c = 180

c = 20

3d + d = 180

4d = 180

d = 45

6 0

3 years ago

Reason abstractly. Are all horizontal lines parallel? Use slope<br> explain how you know.

ohaa [14]

Answer:

All horizontal lines are NOT parallel.

Step-by-step explanation:

We learned that lines go on forever.

If one line is slightly slanted, and the other line is completely straight, these lines are not parallel, as they will meet at some point.

Hope this helped :)

6 0

3 years ago

Find the value of X <br> ASAP

Taya2010 [7]

X= 103
180 - 65 = 115
X + 12 = 115
X = 115 - 12 = 103

6 0

2 years ago

Find the exact value of sin2 theta given sin theta =5/13, 90°<theta <180°

Zepler [3.9K]

Now, we know that 90°< θ <180°, that simply means the angle θ is in the II quadrant, where sine is positive and cosine is negative.

$\bf sin(\theta )=\cfrac{\stackrel{opposite}{5}}{\stackrel{hypotenuse}{13}}\impliedby \textit{now let's find the \underline{adjacent side}}
\\\\\\
\textit{using the pythagorean theorem}\\\\
c^2=a^2+b^2\implies \pm\sqrt{c^2-b^2}=a\qquad 
\begin{cases}
c=hypotenuse\\
a=adjacent\\
b=opposite\\
\end{cases}$

$\bf \pm\sqrt{13^2-5^2}=a\implies \pm\sqrt{144}=a\implies \pm 12 =a \implies \stackrel{II~quadrant}{-12=a}
\\\\\\
therefore \qquad cos(\theta )=\cfrac{\stackrel{adjacent}{-12}}{\stackrel{hypotenuse}{13}}
\\\\
-------------------------------\\\\
sin(2\theta )\implies 2sin(\theta )cos(\theta )\implies 2\left(\frac{5}{13} \right)\left( \frac{-12}{13} \right)\implies -\cfrac{120}{169}$

3 0

3 years ago

Sara can take no more than 22 pounds of luggage on a trip. Her suitcase weighs 112 ounces. How many more ponds can she pack with

Elena L [17]

112oz(lb/16oz)+x≤22

7+x≤22

x≤15

So she can pack 15 more pounds without going over the limit.

7 0

3 years ago