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3 years ago

SOMEONE HELP PLEASE!!!!

Mathematics

1 answer:

Sever21 [200]3 years ago

8 0

Answer:

Step-by-step explanation:

should be c

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If you flip a coin 44 times what is the best prediction possible for the number of times it’ll land on heads

nika2105 [10]

Answer:

12% chance of 22

35% chance of 21, 22, or 23

55% chance of 20, 21, 22, 23, or 24

How can 22 be a good prediction when it's wrong 88% of the time?

I'd say from 20 to 24 is a good prediction without being trivial.

Step-by-step explanation:

C(n,k) = n Choose k = n! / (k! (n-k)!)

aka binomial coefficient

aka from n things choose k

To get probability of getting heads 22 times in 44 tries, you divide number of ways to get heads 22 times by number of ways to assign heads or tails to each throw.

Two ways to assign H or T to first, times two ways for second throw,

gives 2^44. That's the denominator.

Number of ways to get heads 22 times is the same as number of ways to choose which 22 flips of 44 are to be heads, or C(44,22)

To get 12% calculate C(44,22)/2^44

To get 55% calculate C(44,20)/2^44 + ... + C(44,24)/2^44

8 0

3 years ago

Find the sum of the following geometric sequences a) 6 terms (-4, 12, -36,...)

posledela

Answer:

S₆ = 728

Step-by-step explanation:

the sum to n terms of a geometric sequence is

$S_{n}$ = $\frac{a_{1}(r^{n}-1) }{r-1}$

where a₁ is the first term and r the common ratio

here a₁ = - 4 and r = $\frac{a_{2} }{a_{1} }$ = $\frac{12}{-4}$ = - 3 , then

S₆ = $\frac{-4((-3)^{6}-1) }{-3-1}$

= $\frac{-4(729-1)}{-4}$

= 729 - 1

= 728

6 0

2 years ago

What equation represents the parabola?

olganol [36]

Answer:

The first option, x² = -8(y-2).

Explanation:

The first step is to find the vertex. We define the vertex as the point on a parabola that is equidistant from the focus and directrix. The focus is at (0,0) and the directix has the equation of y = 4, so we can easily find that the vertex is at (0,2). Vertex form is y = a(x-h)²+k, where (h,k) is the vertex of the parabola, so we can plug in (0,2) to get y = a(x-0)²+2 ⇒ y = ax²+2. Secondly, we know that a = $\frac{1}{4p}$ , where p is defined as the distance (and direction) from the vertex to the focus. We know that the vertex is at (0,2) and the focus is at (0,0), so the distance is 2. Because the focus is below the vertex, though, the parabola must open downwards, and therefore, p = -2. a = $\frac{1}{4(-2)}$ ⇒ $-\frac{1}{8}$ . Now, the equation is y = $-\frac{1}{8}$ x²+2. None of the answers are in this particular form, though. The entire equation is multiplied by -8 to produce -8y = x²-16. 16 is added on both sides to get x² = -8y+16. This is simplified to x² = -8(y-2), and we can see that the answer is the first option.