Question

20∙lg∙(1·10^2/5·10^-8 )

Answer 1

$20lg\left ( \frac{10^2}{5\cdot 10^{-8}} \right )=20lg\left ( \frac{10^{10} }{5}\right ) =20(10-lg5)=200-20lg5$

Answer 2

It looks like you're trying to calculate the expression 20∙lg(1·10^2/5·10^-8). I assume you mean "lg" to be the base-10 logarithm, commonly denoted as log10.

Let's break down the expression step by step:

1. 10^2 = 100
2. 5·10^-8 = 0.00000005

So, the expression becomes:

20∙log10(100 / 0.00000005)

Now, let's calculate the division inside the logarithm:

100 / 0.00000005 = 2,000,000,000

Now we have:

20∙log10(2,000,000,000)

Calculating the logarithm:

log10(2,000,000,000) ≈ 9.301

Finally, multiply by 20:

20∙9.301 ≈ 186.02

Therefore, the value of the expression 20∙lg(1·10^2/5·10^-8) is approximately 186.02.