How can 0.00004 be expressed using scientific notation?

To express a number in scientific notation, it is necessary to represent it as a product of a coefficient and a power of ten. The coefficient must be a number between 1 and 10, and the exponent of ten indicates how many places to move the decimal point to achieve the standard form of the number.

In the case of the number 0.00004, we begin by moving the decimal point until there is only one non-zero digit to its left. Moving the decimal point 5 places to the right gives us the number 4. Therefore, we can express 0.00004 as 4, with the understanding that we moved the decimal point 5 places to the right. This is represented by a negative exponent in scientific notation, specifically, as 4 x 10^-5.

Thus, in scientific notation, 0.00004 is correctly expressed as 4 x 10^-5, making this the proper representation in the given context.