An author published a book which was being sold online. The first month the author sold 21000 books, but the sales were declining steadily at 12% each month. If this trend continues, how many total books would the author have sold over the first 9 months, to the nearest whole number?

the answer is c.

step-by-step explanation:

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: