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inessss [21]
2 years ago
7

Sin8x=8sinxcosxcos2xcos4x proving trig identity?

Mathematics
1 answer:
weeeeeb [17]2 years ago
7 0
sin 8 x = 2 sin 4x  cos 4x =
= 2 * 2  sin 2x  cos 2x  cos 4 x =
= 4 * 2  sin x  cos x  cos 2x  cos 4x =
= 8  sin x  cos x  cos 2x  cos 4x    ( correct )  
You might be interested in
Three people toss a fair coin and the odd one pays for coffee. if the coins all turn up the same, they are tossed again. find th
dexar [7]

Since the problem doesn’t give a definite question, here are the possible questions and answer:

P(fewer than 4 tosses) 
= P(one toss) + P(two toss) + P(3 toss) 
= (3/4) + (3/4)(1/4) + (3/4)(1/4)^2 
= 0.984375 


Expected value 
= 1 / p 
= 1 / (3/4) 
= 4 / 3 

Variance 
= (1 - p) / p^2 
= (1 - (3/4)) / (3/4)^2 
= (1/4) / (9/16) 
= 4 / 9 

Standard deviation 
= sqrt(Variance) 
= sqrt(4 / 9) 
= 2 / 3

8 0
2 years ago
jill mixes two types of concentrations od hci (hydrochloric acid) 0.375 liters of 25% hydrochloric acid and 0.625 liters of 65%
Sonja [21]

Answer:

The concentration of HCl in the mixture is 1L of 50% HCl

Step-by-step explanation:

Here, we want to know the percentage of HCl present which refers to the its concentration.

Firstly, the total volume we have is 0.375 + 0.625 = 1 L

we can calculate the percentage as follows;

The percentage of the 25% present is 37.5%

while the percentage of the 75% present is 62.5%

When we say the percentage present, we are referring to the amounts of the total liters which is 1 present.

So the concentration of the final mixture will be;

(37.5% of 25) + (62.5% of 65)

= 9.375% + 40.625%

Adding both gives = 50%

So the concentration we have is 1L of 50% HCl

7 0
2 years ago
The time intervals between successive barges passing a certain point on a busy waterway have an exponential distribution with me
lisov135 [29]

Answer:

a) <u>0.4647</u>

b) <u>24.6 secs</u>

Step-by-step explanation:

Let T be interval between two successive barges

t(t) = λe^λt where t > 0

The mean of the exponential

E(T) = 1/λ

E(T) = 8

1/λ = 8

λ = 1/8

∴ t(t) = 1/8×e^-t/8   [ t > 0]

Now the probability we need

p[T<5] = ₀∫⁵ t(t) dt

=₀∫⁵ 1/8×e^-t/8 dt

= 1/8 ₀∫⁵ e^-t/8 dt

= 1/8 [ (e^-t/8) / -1/8 ]₀⁵

= - [ e^-t/8]₀⁵

= - [ e^-5/8 - 1 ]

= 1 - e^-5/8 = <u>0.4647</u>

Therefore the probability that the time interval between two successive barges is less than 5 minutes is <u>0.4647</u>

<u></u>

b)

Now we find t such that;

p[T>t] = 0.95

so

t_∫¹⁰ t(x) dx = 0.95

t_∫¹⁰ 1/8×e^-x/8 = 0.95

1/8 t_∫¹⁰ e^-x/8 dx = 0.95

1/8 [( e^-x/8 ) / - 1/8 ]¹⁰_t  = 0.95

- [ e^-x/8]¹⁰_t = 0.96

- [ 0 - e^-t/8 ] = 0.95

e^-t/8 = 0.95

take log of both sides

log (e^-t/8) = log (0.95)

-t/8 = In(0.95)

-t/8 = -0.0513

t = 8 × 0.0513

t = 0.4104 (min)

so we convert to seconds

t = 0.4104 × 60

t = <u>24.6 secs</u>

Therefore the time interval t such that we can be 95% sure that the time interval between two successive barges will be greater than t is <u>24.6 secs</u>

6 0
2 years ago
Celeste can spend no more than $30 to buy quinoa and rice. She will pay $5 per pound for quinoa and $2 per pound for rice. Which
Furkat [3]

Can you send pic of graph

Step-by-step explanation:

Pls

5 0
2 years ago
Read 2 more answers
Which will result in a perfect square trinomial? (3 x minus 5)(3 x minus 5) (3 x minus 5)(5 minus 3 x) (3 x minus 5)(3 x + 5) (3
Sphinxa [80]

Answer:

(3x-5)*(3x-5)

Step-by-step explanation:

Perfect square trinomial is defined by the follow way

(a+b)^{2}=a^{2} +2ab+b^{2}

Now we can rewrite (a+b)^{2} as (a+b)(a+b)  because a squared add is equal to multiply the add by itself one time

if we make a=3x and b=-5 we can see tha the first answer is the only option that could be a  perfect square triomial

6 0
2 years ago
Read 2 more answers
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