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3 years ago

Which number sentence is always true? Select all that apply.

Mathematics

2 answers:

Kitty [74]3 years ago

6 0

I only remember negative + negative is always negative...

Hatshy [7]3 years ago

3 0

1. false
2. true
3. false
4. true
5.true
6.true

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Find dy/dx given that y = sin x / 1 + cos x

kobusy [5.1K]

Answer:

$\frac{1}{1 + \cos(x) }$

Step-by-step explanation:

$y = \frac{ \sin(x) }{1 + \cos(x) }$

differentiating numerator wrt x :-

(sinx)' = cos x

differentiating denominator wrt x :- 

(1 + cos x)' = (cosx)' = - sinx

Let's say the denominator was "v" and the numerator was "u"

$(\frac{u}{v} )' = \frac{v. \: (u)' - u.(v)' }{ {v}^{2} }$

here,

since u is the numerator u= sinx and u = cos x
v(denominator) = 1 + cos x; v' = - sinx

$= \frac{((1 + \cos \: x) \cos \: x )- (\sin \: x. ( - \sin \: x) ) }{( {1 + \cos(x)) }^{2} }$

$= \frac{ \cos(x) + \cos {}^{2} (x) + \sin {}^{2} (x) }{(1 + \cos \: x) {}^{2} }$

since cos²x + sin²x = 1

$= \frac{ \cos \: x + 1}{(1 + \cos \: x) {}^{2} }$

diving numerator and denominator by 1 + cos x

$= \frac{1}{1 + \cos(x) }$

6 0

3 years ago

Bethany can mow her family’s lawn in 4 hours. Her brother Colin can mow the lawn in 3 hours. Which equation can be used to find

Alina [70]

Answer:

Step-by-step explanation:

t/4+t/3=1

(3t+4t)/12=1

7t/12=1

7t=12

t=12/7

x=(12/7)hours

7 0

2 years ago

Cinderella ordered different colored fabrics to make a new dress for the upcoming ball. 20% were blue, 1 10 were white, 40% were

arsen [322]

We know that
20% --------------> were blue
1/10---> 0.10----> 10%--------------> were white
40% ---------------> were silver

and
9 ---------> were gold
so
gold=100%-(20%+10%+40%)-------> 100%-70%------> 30%

30% ---------------------> is equal to 9
10% (were white)-------> X
X=10%*9/30%------> x=3

the answer is
3

3 0

3 years ago

What is Decrease 90 by 1/2

devlian [24]

Answer:

Step-by-step explanation:

$\frac{1}{2}$ × 90 = 45