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natita [175]
3 years ago
15

The 12th term of the arithmetic sequence is 10.5. The 18th term of this sequence is 13.5. Find the common difference and the fir

st term
Mathematics
1 answer:
xxMikexx [17]3 years ago
7 0

Answer:

common difference is 0.5

first term is 5

Step-by-step explanation:

<em>use </em><em>the </em><em>formula</em><em> for</em><em> </em><em>the</em><em> </em><em>nth </em><em>term </em><em>of </em><em>an </em><em>ap </em><em>Tn=</em><em>a+</em><em>(</em><em>n-1)</em><em>d</em>

<em>T12=</em><em>1</em><em>0</em><em>.</em><em>5</em>

<em>T18=</em><em>1</em><em>3</em><em>.</em><em>5</em>

<em>therefore</em><em> </em><em>come </em><em>up </em><em>with </em><em>two </em><em>equations</em>

<em>T12=</em><em>a+</em><em>(</em><em>1</em><em>2</em><em>-</em><em>1</em><em>)</em><em>d</em>

<em>1</em><em>0</em><em>.</em><em>5</em><em>=</em><em>a+</em><em>1</em><em>1</em><em>d</em><em>(</em><em>1</em><em>s</em><em>t</em><em> </em><em>equation</em><em>)</em>

<em>T18</em><em>=</em><em>a+</em><em>(</em><em>1</em><em>8</em><em>-</em><em>1</em><em>)</em><em>d</em>

<em>1</em><em>3</em><em>.</em><em>5</em><em>=</em><em>a+</em><em>1</em><em>7</em><em>d</em><em>(</em><em>2</em><em>n</em><em>d</em><em> </em><em>equation</em><em>)</em>

<em>then </em><em>solve </em><em>both </em><em>as </em><em>a </em><em>simultaneous</em><em> </em><em>equation</em>

<em>a+</em><em>1</em><em>1</em><em>d</em><em>=</em><em>1</em><em>0</em><em>.</em><em>5</em>

<em>a+</em><em>1</em><em>7</em><em>d</em><em>=</em><em>1</em><em>3</em><em>.</em><em>5</em>

<em> </em><em> </em><em> </em><em> </em><em>-6d/</em><em>-</em><em>6</em><em>=</em><em>-</em><em>3</em><em>/</em><em>-</em><em>6</em>

<em> </em><em> </em><em> </em><em> </em><em> </em><em> </em><em> </em><em> </em><em> </em><em> </em><em> </em><em> </em><em> </em><em>d=</em><em>0</em><em>.</em><em>5</em>

<em>use </em><em>one </em><em>of</em><em> the</em><em> </em><em>equations</em><em> </em><em>to </em><em>find </em><em>the </em><em>first</em><em> </em><em>term</em>

<em>a+</em><em>1</em><em>1</em><em>(</em><em>0</em><em>.</em><em>5</em><em>)</em><em>=</em><em>1</em><em>0</em><em>.</em><em>5</em>

<em>a+</em><em>5</em><em>.</em><em>5</em><em>=</em><em>1</em><em>0</em><em>.</em><em>5</em>

<em>a=</em><em>1</em><em>0</em><em>.</em><em>5</em><em>-</em><em>5</em><em>.</em><em>5</em>

<em>a=</em><em>5</em>

<em>I </em><em>hope </em><em>this </em><em>helps</em>

<em>please </em><em>mark</em><em> </em><em>as </em><em>brainliest</em>

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The formulae for Constructing a 99% confidence interval is given below as

u = x + Zα/2 × (s/√n)........... For the upper limit

u = x - Zα/2 × (s/√n)........... For the lower limit

Where u = population mean

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n = sample size = 108.

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We are making use of our z test because sample size is greater than 30 ( n = 108).

By substituting the parameters, we have that

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u = 98.2 + 2.58 ( 0.0616)

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For lower limit

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u = 98.2 - 2.58 ( 0.64/√108)

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_____

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