1. Exercise 18, section 5.4. Compute 90, 91, 92, 93, 94 and 95. Make a conjecture about the units digit of 9n where n is a posit
1 answer:
Answer:
n is a positive integer and here 90, 91, 92, 93, 94 and 95 is 9⁰ = 1
9¹ = 9
9² = 81
9³ = 729
9⁴ = 6561
9⁵ = 59049
so mathematical induction is prove given below.
Step-by-step explanation:
9⁰ = 1
9¹ = 9
9² = 81
9³ = 729
9⁴ = 6561
9⁵ = 59049
lets us consider by P (n) for the base case n = 0 then 9⁰ = 1 So P (1) is true
k ≥ 1so consider all integers
1≤l≤ k
There is a need to prove P (k+1)
if k is odd
=
.9.
is 9 so
= 9 +10m
then
= 9 ( 9 + 10m)
=81 + 10 (9m)
so digit is 1 and k +1 is even
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-------- = ---------
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Then, to solve for x, we would divide both sides by 2.5. (If you don't know why that is, please let me know and I'll elaborate).
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20×2
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Now, we can see that this is just a simple proportion problem. For every 2.5 cm of height of the flower, we are 2 cm from the opening, or aperture. For every 20 cm of height, how far are we? We can set up the problem like this:
20 ............2.5
-------- = ---------
...x ............. 2
where x is the unknown distance to the aperture from the flower. Now, we just need to get x by itself. A typical way of solving something like this is by doing "butterfly multiplication" which is really just a shortcut haha. Anyway, I can rewrite that equation ^ as:
20×2 = 2.5 × x
Then, to solve for x, we would divide both sides by 2.5. (If you don't know why that is, please let me know and I'll elaborate).
We would then have:
20×2
------- = x
2.5
Which then simplifies to:
x = 16
Try using the same logic for your second question, and if you get stuck, I'd be happy to help! please let me know if any of this doesn't make sense. :)