Health The length L (in mm) of the mesiodistal crown of the first molar of a human fetus i...

Health The length L (in mm) of the mesiodistal crown of the first molar of a human fetus is approximated by

where t is the number of weeks since conception.*

(a) At how many weeks is the length about 4 mm?

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(b) Explain why the second answer in part (a) does not apply here.

*Based on E. F. Harris, J. D. Hicks, and B. D. Barcroft, “Tissue Contributions to Sex and Race: Differences in Tooth Crown Size of Deciduous Molars.” American Journal of Physical Anthropology. Vol. 115. 2001, p. 223.