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  1. AP Pre Calculus
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How do you find an exponential function given two points?

  1. Substitute the points into y=abxy = ab^xy=abx. 2. Solve the resulting system of equations for 'a' and 'b'.
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How do you find an exponential function given two points?

  1. Substitute the points into y=abxy = ab^xy=abx. 2. Solve the resulting system of equations for 'a' and 'b'.

How do you determine if a data set represents exponential growth or decay?

  1. Check if the y-values have a constant ratio for equally spaced x-values. 2. If the ratio is > 1, it's growth; if < 1, it's decay.

How do you solve for 't' in the equation P(t)=P0btP(t) = P_0 b^tP(t)=P0​bt?

  1. Divide by P0P_0P0​: P(t)/P0=btP(t)/P_0 = b^tP(t)/P0​=bt. 2. Take the logarithm of both sides: ln(P(t)/P0)=t∗ln(b)ln(P(t)/P_0) = t * ln(b)ln(P(t)/P0​)=t∗ln(b). 3. Solve for t: t=ln(P(t)/P0)/ln(b)t = ln(P(t)/P_0) / ln(b)t=ln(P(t)/P0​)/ln(b)

How do you convert an exponential function from base 'b' to base 'e'?

  1. Write b=eln(b)b = e^{ln(b)}b=eln(b). 2. Substitute: abx=a(eln(b))x=aeln(b)xab^x = a(e^{ln(b)})^x = ae^{ln(b)x}abx=a(eln(b))x=aeln(b)x

How do you determine the annual growth rate from a function like P(t)=500(1.08)tP(t) = 500(1.08)^tP(t)=500(1.08)t?

The annual growth rate is (1.08 - 1) * 100% = 8%.

How to find the equation of an exponential function given the initial value and growth rate?

  1. Identify the initial value (a). 2. Calculate b = 1 + growth rate (for growth) or b = 1 - decay rate (for decay). 3. Write the equation: f(x)=abxf(x) = ab^xf(x)=abx

How do you use exponential regression on a calculator?

  1. Enter data into lists. 2. Select exponential regression function. 3. Store the regression equation.

How do you determine the doubling time of an exponential function?

  1. Set 2=bt2 = b^t2=bt. 2. Solve for t using logarithms: t=ln(2)ln(b)t = \frac{ln(2)}{ln(b)}t=ln(b)ln(2)​

How do you determine the half-life of an exponential function?

  1. Set 0.5=bt0.5 = b^t0.5=bt. 2. Solve for t using logarithms: t=ln(0.5)ln(b)t = \frac{ln(0.5)}{ln(b)}t=ln(b)ln(0.5)​

How do you analyze the effect of adding a constant k to the function f(x)=abxf(x) = ab^xf(x)=abx?

The new function is f(x)=abx+kf(x) = ab^x + kf(x)=abx+k. This shifts the horizontal asymptote from y = 0 to y = k.

What is the general formula for an exponential function?

f(x)=abxf(x) = ab^xf(x)=abx

Given two points (x1, y1) and (x2, y2) on an exponential function, what are the formulas for 'a' and 'b'?

a=y1a = y1a=y1, b=y2/y1b = y2 / y1b=y2/y1 (when x1 = 0 and x2 = 1)

What is the formula for continuous growth using the natural base 'e'?

f(x)=exf(x) = e^xf(x)=ex

What is the formula for continuous decay using the natural base 'e'?

f(x)=e−xf(x) = e^{-x}f(x)=e−x

How to find 'b' if given two points (x1, y1) and (x2, y2)?

b=(y2/y1)1/(x2−x1)b = (y2/y1)^{1/(x2-x1)}b=(y2/y1)1/(x2−x1)

Given f(d) = 2^d, what is the equivalent form showing weekly growth?

f(d)=(27)(d/7)f(d) = (2^7)^{(d/7)}f(d)=(27)(d/7)

How do you calculate the growth factor over a specific interval?

Growth factor = bΔxb^{\Delta x}bΔx, where Δx\Delta xΔx is the length of the interval.

What is the formula for exponential growth with an initial value of P0P_0P0​?

P(t)=P0btP(t) = P_0 b^tP(t)=P0​bt

What is the formula for exponential decay with an initial value of A0A_0A0​?

A(t)=A0btA(t) = A_0 b^tA(t)=A0​bt, where 0 < b < 1

How do you find the value of 'e' using a limit?

e=lim⁡n→∞(1+1n)ne = \lim_{n \to \infty} (1 + \frac{1}{n})^ne=limn→∞​(1+n1​)n

Define exponential growth.

Growth increasing at an increasing rate; b > 1 in f(x)=abxf(x) = ab^xf(x)=abx.

Define exponential decay.

Decay decreasing at a decreasing rate; 0 < b < 1 in f(x)=abxf(x) = ab^xf(x)=abx.

What is the general form of an exponential function?

f(x)=abxf(x) = ab^xf(x)=abx, where 'a' is the initial value and 'b' is the base.

Define the natural base 'e'.

A mathematical constant approximately equal to 2.71828, used for continuous growth/decay.

What is exponential regression?

A method to fit an exponential function to a set of data points.

Define the correlation coefficient R2R^2R2 in exponential regression.

A measure of how well the exponential model fits the data.

What are residuals in exponential regression?

The difference between the observed data and the predicted values from the exponential model.

What is 'ln'?

The natural logarithm, the inverse function of exe^xex.

What is an equivalent form of an exponential function?

A different representation of the same function that reveals different properties.

What does the initial value 'a' represent in f(x)=abxf(x) = ab^xf(x)=abx?

The value of the function when x = 0.