Question #a04c1

1 Answer

4.56 * 10^(-3)4.56103

Explanation:

Your goal here is to write your number in normalized scientific notation, which has

color(white)(aa)color(blue)(m) xx 10^(color(purple)(n) color(white)(a)stackrel(color(white)(aaaaaa))(larr))color(white)(acolor(black)("the")acolor(purple)("exponent")aa)aam×10naaaaaaa−−atheaexponentaa
color(white)(a/acolor(black)(uarr)aaaa)aa⏐ ⏐aaaa
color(white)(color(black)("the")acolor(blue)("mantissa")a)theamantissaa

and

1 <= |color(blue)(m)| < 10" " " "color(darkorange)("(*)")1|m|<10 (*)

As you know, you have

10^0 = 1100=1

This means that you can write your initial number as

color(blue)(0.00456) * 10^color(purple)(0)0.00456100

Now, to start converting the number to scientific notation, multiply it by 1 = color(blue)(10)/color(purple)(10)1=1010 -> keep in mind that we can multiply the number by 11 because that leaves its value unchanged!

color(blue)(0.00456) * 10^color(purple)(0) * color(blue)(10)/color(purple)(10)0.004561001010

You can rewrite this as

color(blue)(0.00456) * color(blue)(10) * 10^color(purple)(0)/color(purple)(10) = color(blue)(0.0456) * 10^color(purple)(-1)0.004561010010=0.0456101

At this point, you must check to see if the new value of the mantissa satisfies condition color(darkorange)("(*)")(*).

Since

1 color(red)(cancel(color(black)(<=))) color(blue)(0.0456) color(red)(cancel(color(black)(<))) 10

you must repeat the process again. This time, you have

color(blue)(0.0456) * 10^color(purple)(-1) * color(blue)(10)/color(purple)(10)

which is equivalent to

color(blue)(0.0456) * color(blue)(10) * 10^color(purple)(-1)/color(purple)(10) = color(blue)(0.456) * 10^color(purple)(-2)

Condition color(darkorange)("(*)") is still not satisfied, so you must repeat the process again. This time, you have

color(blue)(0.456) * 10^color(purple)(-2) * color(blue)(10)/color(purple)(10)

which is equivalent to

color(blue)(0.456) * color(blue)(10) * 10^color(purple)(-2)/color(purple)(10) = color(blue)(4.56) * 10^color(purple)(-3)

Finally, you have

1 <= color(blue)(4.56) < 10" " " "color(darkgreen)(sqrt())

so you can say that

color(darkgreen)(ul(color(black)(0.00456 = 4.56 * 10^(-3))))

Notice that the number written in scientific notation has 3 sig figs, just like the number written in standard form.

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