Arithmetic sequence, help with #18 plz
1 answer:
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A formula is recursive if it expresses the term in terms of the previous one(s)
In this case, every term is 7 more than the previous one, so the formula for will only involve
:
In fact, this formula is simply saying: for every index , the term with that index is 7 more than the term before.
Also, we have to specify the starting point (otherwise we would go backwards indefinitely), so the complete recursive formula is
which means: start with 2 and generate every other term by adding 7 to the previous one.
Answer:
The area of the trapezoid is 57.5 square inches
Step-by-step explanation:
we know that
The trapezoid QRST can be divided into a rectangle QRDT and an isosceles right triangle RSD
see the attached figure to better understand the problem
step 1
The area of rectangle is given by the formula
we have
----> altitude
substitute
step 2
Find the area of the isosceles right triangle
The area of triangle is given by the formula
we have
---> because is an isosceles triangle
substitute
step 3
Adds the areas
