Find a28 in the arithmetic sequence: 5.8, 3.5, 1.2, -1.1,

-56.3

Step-by-step explanation:

We don't have to much guessing because it tells us it is arithmetic which means it has a common difference.

That is a term minus it's previous will be the same.

In general:

with if you wanted the recursive form.

You can also find the explicit form which would be more helpful for our task of finding the 28th term.

is the explicit form where is the common difference and is the first term.

Inputting -2.3 for and 5.8 for :

Now the 28th term or can be found by replacing n with 28:

explanation:

infrared radiation has wavelength in the range between 700 nm and 1 mm. lets' convert these values into scientific notation, keeping in mind that:

let's start from the lower value, we have:

(we moved the dot two places to the left, so we increased the exponent by 2 units, from -9 to -7)

the higher value is:

so, the range of wavelength of infrared radiation is: