Question about Texas Instruments TI-84 Plus Calculator
I have no idea what can of data you have, so I am taking a theoretical stance. In a radioactive decay the period of half life is the time after which half the nuclei have desintegrated. Let us call that period tau τ.
The constant, usually called lambda, λ appears in the expoential. It is the constant term that multiplies the time variable, t.
If you have y1 nuclei at a time t, and y2 nuclei at time t+ τ., the ratio y2/y1 =1/2. It is also equal to e^(-λ* τ). Thus
e^(-λ* τ) =1/2.
and ln(e^(-λ* τ)) = ln(1/2)=-ln(2). But since ln(e¨(x)) = x, we get
-λ* τ= - ln(2) and
λ= ln(2)/ τ
In the enclosed screen capture the equation e^(-λ* τ) =1/2 is solved for λ
If you have experimental data, or a radioactive decay curve drawn you can obtain the constant λ , as the negative of the slope of the function at t=0. See on following graph. Disregard the values of the function before t=0 ( I should have restricted the window to the first quadrant.) The function drawn is e^(-0.365t)
Hope it helps.
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A mathematical statement used to evaluate a value. An equation can use any combination of mathematical operations, including addition, subtraction, division, or multiplication. An equation can be already established due to the properties of numbers (2 + 2 = 4), or can be filled solely with variables which can be replaced with numerical values to get a resulting value. For example, the equation to calculate return on sales is: Net income ÷ Sales revenue = Return on Sales. When the values for net income and sales revenue are plugged into the equation, you are able to calculate the value of return on sales.
There are many types of mathematical equations.
1. Linear Equations y= mx + b (standard form of linear equation)
2. Quadratic Equations y= ax^2+bx+c
3. Exponential Equations y= ab^x
4. Cubic Equations y=ax^3+ bx^2+cx+d
5. Quartic Equations y= ax^4+ bx^3+ cx^2+ dx+ e
6. Equation of a circle (x-h)^2+(y-k)^2= r^2
7. Constant equation y= 9 (basically y has to equal a number for it to be a constant equation).
8. Proportional equations y=kx; y= k/x, etc.
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