4. Create the recursive definition for the sequence: 100,80,60,---

Mathematics

2 answers:

Deffense [45]3 years ago

6 0

Answer:

40 is the answer

Step-by-step explanation:

20×5,20×4,20×3,20×2

GalinKa [24]3 years ago

3 0

The answer would be 40. Subtract 20 each time

You might be interested in

How much pure acid should be mixed with 6 gallons of a 20% acid solution in order to get a 90% acid solution?

beks73 [17]

So, how much acid is there in 6 gallons? well is 20% acid or (20/100), so the amount of acid in it just (20/100) * 6 or 1.2, the rest is say water.

now, if we want a 90% solution, and say we add "y" gallons, how much acid is in it? well (90/100) * y, or 0.9y.

now let's add "x" gallons of pure acid, now, pure acid is just pure acid, so is 100% acid, how much acid is there in it? (100/100) * x, or 1x or just x.

we know whatever "x" and "y" amounts are, they -> x + 6 = y

and we also know that x + 1.2 = 0.9y

$\bf \begin{array}{lccclll}
&\stackrel{gallons}{acid}&\stackrel{acid~\%}{quantity}&\stackrel{acid~gallons}{quantity}\\
&------&------&------\\
\textit{pure acid}&x&1.00&x\\
\textit{20\% sol'n}&6&0.20&1.2\\
------&------&------&------\\\
mixture&y&0.90&0.9y
\end{array}
\\\\\\
\begin{cases}
x+6=\boxed{y}\\
x+1.2=0.9y\\
----------\\
x+1.2=0.9\left( \boxed{x+6} \right)
\end{cases}
\\\\\\
x+1.2=0.9x+5.4\implies x-0.9x=5.4-1.2\implies 0.1x=4.2
\\\\\\
x=\cfrac{4.2}{0.1}\implies x=\stackrel{gallons}{42}$

3 0

3 years ago

Please please help i have this midterm due tomorrow

jek_recluse [69]

You should know that cos2x =1-2sin^2x, so you substitute and take everything to one side. After that I took out a common factor of sinx which simplified my equation and gave me my first solution x=0. I go and find the relative acute angle in my second solution 2sinx+1=0, and as the value of raw is negative you have to obtain two solutions from where sin is negative. And you are given all you solutions. Hopefully this helps, if you don’t understand what I am saying just ask me anything. :)