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This guide explores the fundamentals of exponential functions represented by f(x) = a * c^b(x-h) + k. We will analyze the roles of parameters a, b, and c, discussing how they affect vertical and horizontal stretches, initial values, and horizontal asymptotes. Additionally, we'll examine how the base influences the function's increase or decrease. Examples illustrate transformations and the identification of function characteristics. Join us in discovering the key elements that govern exponential functions and their applications.
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Basic Exponential Function f(x)=acbx exponential function in base c asymptote: x-axis a affects the vertical stretch a is also the initial value a can also flip the function b affects the horizontal stretch b is the period
Role of the parameter “a” and “c” Where parameter b must always be positive!!! if c > 1 if 0 < c < 1 a > 0 a < 0
Examples For each of the following, determine the base and indicate if the function is increasing or decreasing. Base = 3/4 Base = 3/2 Base = 3/2 Decreasing Decreasing Increasing
Exponential Functions f(x)=acb(x-h) + k h shifts the initial value to the right or left k shifts the initial value up or down k is the horizontal asymptote
Exponential Functions The rule f(x)=acb(x-h) + k can be re-written in the form: f(x)=acx + k where the function passes through the point (0, a + k) and has y = k as its asymptote
Example Convert to the form f(x)=acx + k f(x) = 5(3)2(x+1) + 7 f(x) = 5(32) (x+1) + 7 f(x) = 5(9)(x+1) + 7 f(x) = 5(9x.91)+ 7 f(x) = 45(9x)+ 7 f(x) = 45(9)x+ 7
Example Convert to the form f(x)=acx + k f(x) = -3(2)3x+1 + 4 f(x) = -3(2)3(x+1/3) + 4 f(x) = -3(8)(x+1/3) + 4 f(x) = -3(8x.81/3)+ 4 f(x) = -3(8x.2)+ 4 f(x) = -6(8x)+ 4 f(x) = -6(8)x+ 4
Example If the point A(2,9) belongs to the graph of an exponential function of the form y = cx, determine the rule 9 = c2 3 = c y = 3x
Example If the points A(1,4) and B(2,12) belong to the graph of an exponential function of the form y = acx, determine the rule 4 = ac1 12 = ac2 4 = a 12 = a c1 c2 4 = 12 c1 c2 4c2 = 12 c1 4c = 12 c = 3
Exponential Functions f(x)=acb(x-h) + k FINDING THE ZEROS Plug in y=0 and solve for x! y=5(3)x-2 – 15 0=5(3)x-2 – 15 15=5(3)x-2 15/5=(3)(x-2) 3=(3)(x-2) 1 = x-2 3=x
Euler's Number • A special irrational base of the exponential function • has a value of 2.71828… • abbreviated as e Examples: y = ex y = 3(e)x-1 - 2 • y = ex
Example √e(e2x-1)(ex)=√e3