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Ronch [10]
2 years ago
10

In an arithmetic sequence, = 5 and = 11.

Mathematics
1 answer:
Free_Kalibri [48]2 years ago
5 0

Answer:

1134.62 (THE SUM OF 20 TERMS)

Step-by-step explanation:

First we write out our given information:

a8=2a2

a11=18

an is an arithmetic sequence.

Where here an means the nth term of our sequence.

What does an arithmetic sequence mean? It means to get to the next term in your sequence you add a constant (c) each time:

an+1=an+c

Equivalently:

an+1−an(n+1)−n=c

So an is of slope c (c2 is another constant):

an=cn+c2

Where here c2=a0 (Substitute in n=0 and see why that has to be the case if we let a0 exist)

Now we use the other given information to try to come up with a solution.

Let n=2:

a2=2c+c2

Let n=8, using the above equation we have:

a8=8c+c2=2a2=4c+2c2

Let n=11

a11=18

a11=11c+c2

But a11−a8=(11c+c2)−(8c+c2)=3c

Hence, a11=3c+a8

a11=3c+4c+2c2=18

a11=3c+8c+c2=18

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A grasshopper jumps straight up from the ground with an initial vertical velocity of 8 feet per second. After how many seconds w
vlabodo [156]

Answer:

Problem 1 : After 0.25 s

Problem 2 : The squirrel doesn't reach the ground before the nut

Step-by-step explanation:

Problem 1

This is a standard physics problem

The equation that defines the movement of the grasshopper given the initial velocity, and the acceleration is the following

Distance =  Do + Vo*t + 0.5*a*t^2

Where

Do is the initial distance.

(Do = 0, because the grasshopper is on the ground and we choose the reference system there)

Vo is the initial velocity = 8 feet/sec

a is the acceleration that is exerted on the body (in this case a = g = -9.8 m/s^2 = - 32.174 feet per second per second.)

t is the time

We substitute in the equation, and solve for t (time)

Distance =  Do + Vo*t + 0.5*a*t^2

(1 foot)=  (0)+ (8 feet/s)*t + 0.5*(-32.174 feet/s^2)*t^2

Solving this equation, we get that

t = 0.25 s

Problem 2

This problem is similar to the previous one

We apply the same formula

D =  Do + Vo*t + 0.5*a*t^2

But in this case, we are going in the opposite direction, and we have an initial distance.

Do = 27 feet

Vo is the initial velocity of the nut = -6 feet/s

D = 0  (Ground)

We substitute in the equation, and solve for t (time)

(0) =  (27) + (-6 feet/s)*t + 0.5*(-32 feet/s^2)*t^2

t = 1.125 s  <  2s

The nut reaches ground in 1.125 s, so the squirrel doesn't reach the ground before the nut

4 0
3 years ago
In triangle ABC angle C 105° B 45° BD median of triangle ABC find the angle bdc
antiseptic1488 [7]

Answer:

30

Step-by-step explanation:

105 + 45 +  bdc = 180

bdc=30

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