Combine physical and biological half-lives to find how quickly material is removed from the body. Radioactive decay and biological elimination contribute together, giving Tₑ = (T_b × T_p)/(T_b + T_p). The effective half-life is shorter than either half-life alone.
Choose the units for each input. If one half-life is in days and the other is in years, the calculator converts them to matching units. The member worked solution shows that conversion before applying the formula.
Results, input checks, source references and accuracy notes are free. Paid membership adds the step-by-step solution and calculator keystrokesKey sequences for 14 calculator optionsScientific — commonly exam-legalTI-30XaTI-30X IIS / IIBTI-30XS MultiViewTI-34 MultiViewTI-36X ProCasio fx-991EX ClassWizCasio fx-115ES PlusCasio fx-300ES PlusSharp EL-W516TOn screen, no handheld neededRadCon calculator (on screen)Graphing / programmable — practice at homeTI-84 Plus CE (and TI-83/84 family)Casio fx-9750GIII / fx-9860GIIIHP 35sNot sure which you haveGeneric scientificChoose the calculator you use to practice. Check with your testing site which models are allowed in the exam..
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