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VLD [36.1K]
4 years ago
15

The observation deck is about 20 m above sea level. From the observation deck, the angle of depression of the boat is 6 degrees.

How far is the boat from the lighthouse?
Mathematics
1 answer:
Leno4ka [110]4 years ago
7 0
 θ\ 6 degrees
     \
       \     so the θ= 180-90-6 =84 degrees so we need to find x  
20m   \      tan (84)=x/20 
  ____  \      x=20 tan(84) 
      x         x=190.287   
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From 1995 - 2008 in the US 648 people were struck by lightening. 531 of them were men. You want to see if this observation diffe
Gre4nikov [31]

Answer:

Because z is higher than any given value in the chart we come to the conclusion To reject null hypothesis

Step-by-step explanation:

Sample proportion = p= 531/648 = 0.8194

This is the proportion of men that were hit by lightening

Null hypothesis: H0: p = 0.5

Alternate hypothesis: H1: p ≠ 0.5

Test statistics z = 0.8194-0.5/(√0.5x0.5/648)

= 0.8194-0.5/√0.0003858

= 0.3194/0.019642

= 16.26

Since the z > 1.96 (at 5% significance) we reject the null hypothesis.

Therefore in conclusion we say z is higher than given values in the chart so we reject null hypothesis.

Please check attachment!

3 0
3 years ago
Of 1800 students enrolled in school 55% are girls. of the girls attending this school 30% take the bus to school
leonid [27]
55% of 1800 = 0.55(1800) = 990...so there are 990 girls in the school

30% of 990 = 0.30(990) = 297...so there are 297 girls who take the bus
7 0
3 years ago
the odds of rolling a certain number on a single die is 1 chance in 6 rolls. in course of a game, someone rolled 3 fives. accord
Zina [86]

Answer:

18

Step-by-step explanation:

The expected value is the probability times the frequency.

3 = 1/6 × n

n = 18

Note: the use of the word "odds" is very misleading here.  Odds are the ratio of number of successes to number of failures:

S / F

Probability is the ratio of number of successes to number of all outcomes:

S / (S + F)

So the probability of rolling a 5 is 1/6.  The odds of rolling a 5 is 1/5.

Furthermore, the word "must" is also incorrect.  The player didn't <em>have</em> to roll 18 times.  They could have rolled three times and gotten a 5 each time.  Or they could have rolled 100 times.  18 is simply the most <em>likely </em>number of rolls needed to get three 5's.

6 0
3 years ago
A recursive rule for a geometric sequence is a1=3;an=12an−1 . What is the explicit rule for this sequence?
ehidna [41]
From the recursive rule, you can tell the initial value is 3 and the common ratio is 12. The explicit rule is always
.. (n-th term) = (initial value)*(common ratio)^(n -1)

Subsituting the values you know, you have
.. an = 3*12^(n-1)
6 0
3 years ago
(c). It is well known that the rate of flow can be found by measuring the volume of blood that flows past a point in a given tim
aleksklad [387]

(i) Given that

V(R) = \displaystyle \int_0^R 2\pi K(R^2r-r^3) \, dr

when R = 0.30 cm and v = (0.30 - 3.33r²) cm/s (which additionally tells us to take K = 1), then

V(0.30) = \displaystyle \int_0^{0.30} 2\pi \left(0.30-3.33r^2\right)r \, dr \approx \boxed{0.0425}

and this is a volume so it must be reported with units of cm³.

In Mathematica, you can first define the velocity function with

v[r_] := 0.30 - 3.33r^2

and additionally define the volume function with

V[R_] := Integrate[2 Pi v[r] r, {r, 0, R}]

Then get the desired volume by running V[0.30].

(ii) In full, the volume function is

\displaystyle \int_0^R 2\pi K(R^2-r^2)r \, dr

Compute the integral:

V(R) = \displaystyle \int_0^R 2\pi K(R^2-r^2)r \, dr

V(R) = \displaystyle 2\pi K \int_0^R (R^2r-r^3) \, dr

V(R) = \displaystyle 2\pi K \left(\frac12 R^2r^2 - \frac14 r^4\right)\bigg_0^R

V(R) = \displaystyle 2\pi K \left(\frac{R^4}2- \frac{R^4}4\right)

V(R) = \displaystyle \boxed{\frac{\pi KR^4}2}

In M, redefine the velocity function as

v[r_] := k*(R^2 - r^2)

(you can't use capital K because it's reserved for a built-in function)

Then run

Integrate[2 Pi v[r] r, {r, 0, R}]

This may take a little longer to compute than expected because M tries to generate a result to cover all cases (it doesn't automatically know that R is a real number, for instance). You can make it run faster by including the Assumptions option, as with

Integrate[2 Pi v[r] r, {r, 0, R}, Assumptions -> R > 0]

which ensures that R is positive, and moreover a real number.

5 0
3 years ago
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