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Zorluk: OrtaFunction Notation and Transformations

For the function f(x)=4x3f(x) = 4^x - 3, a new function gg is created by reflecting the graph of y=f(x)y = f(x) across the xx-axis, followed by a vertical translation of cc units upward. The graph of y=g(x)y = g(x) contains the point (2,5)(2, -5). What is the value of the constant cc?

Cevap: 8

Cevap

8
Reflecting the graph of f(x)=4x3f(x) = 4^x - 3 across the xx-axis results in the function f(x)=(4x3)=4x+3-f(x) = -(4^x - 3) = -4^x + 3. Translating this graph vertically upward by cc units defines g(x)=4x+3+cg(x) = -4^x + 3 + c. Substituting the given point (2,5)(2, -5) yields 5=42+3+c-5 = -4^2 + 3 + c, which simplifies to 5=13+c-5 = -13 + c. Adding 1313 to both sides gives c=8c = 8.

Adım Adım Çözüm

1
Reflect the function f(x)f(x) across the xx-axis
f(x)=(4x3)=4x+3-f(x) = -(4^x - 3) = -4^x + 3
Reflecting a graph across the xx-axis is represented by negating the output of the function, which transforms y=f(x)y = f(x) to y=f(x)y = -f(x).
2
Apply the vertical translation upward by cc units to define g(x)g(x)
g(x)=f(x)+c=4x+3+cg(x) = -f(x) + c = -4^x + 3 + c
Translating a function vertically upward by cc units adds cc to the function's expression.
3
Substitute the point (2,5)(2, -5) into g(x)g(x) and solve for cc
c=8c = 8
Since the graph of gg passes through (2,5)(2, -5), substitute x=2x = 2 and g(x)=5g(x) = -5 into the equation: 5=42+3+c-5 = -4^2 + 3 + c. This simplifies to 5=16+3+c-5 = -16 + 3 + c, then 5=13+c-5 = -13 + c, which gives c=8c = 8.

Anahtar Kavram

Function transformations, including vertical reflections and translations
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