Prove the following using a direct proof. Your proof should be expressed in com-plete English sentences.
If a, b, and c are integers such that b is a multiple of a3 and c is a multiple of b2, then c is a multiple of a6.

Respuesta :

Answer:

Proved

Step-by-step explanation:

Given

Integers: a, b, c

Required

Show that c is a multiple of a⁶

First, we need to list out the multiples of a³

[tex]a^3 -> a^3, a^6, a^9, a^{12}...[/tex]

Since b is a multiple of a³, then b can be any of the listed multiples

Next, is to list out the multiples of b²

[tex]b^2 -> b^2,b^4,b^6,b^8,b^{10}....[/tex]

Since c is a multiple of b², then c can be any of the listed multiples

To list out the multiples of a⁶, we have to get the common multiples of a³ and b² in terms of a

Substitute a³ for b in

[tex]b^2 -> b^2,b^4,b^6,b^8,b^{10}....[/tex]

[tex](a^3)^2 -> (a^3)^2,(a^3)^4,(a^3)^6,(a^3)^8,(a^3)^{10}....[/tex]

[tex]a^6 -> a^6,a^{12},a^{18},a^{24},a^{30}....[/tex]

Recall that c is a multiple of b²

From the above listed multiples, we have a⁶ listed as one of the multiple; Hence, c is a multiple of a

Yes C should be multiple of [tex]a^6[/tex]

Calculation of the multiple:

Since it is mentioned that b should be the multiple of [tex]a^3[/tex]

So,

[tex]b = a^3R[/tex] here some integer should be R

And, the c should be multiple of [tex]b^2[/tex]

So,

[tex]C = b^2 r[/tex] for some integer r

Now we have to substitute the value of b from the first equation

i.e.

[tex]C = (a^3R)^2r = a^6 (R^2r)[/tex]

Here [tex]R^2r[/tex] is some integer

so,

[tex]C = a^6R'[/tex]

Therefore, we can say that Yes C should be multiple of [tex]a^6[/tex]

Learn more about multiple here: https://brainly.com/question/24146205