2) Consider the function \( f(x)=2 x^{2} \) and \( p(x)=\left(\frac{1}{2}\right)^{x} \). a) Restrict the domain of \( f \) so that the inverse of \( f \) will also be a function. b) Write down the equation of the inverse of \( p \) in the form \( p^{-1}(x)=\ldots \) c) If the inverse of another function is \( g^{-1}(x)=2 x-4 \). Determine the equation of \( g(x) \).
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Bonus Knowledge
To restrict the domain of the function \( f(x) = 2x^2 \) so that its inverse is also a function, you can choose either the non-negative or non-positive part of the function. A common restriction is to let \( x \geq 0 \). This way, \( f \) is one-to-one on this interval, making it possible to find a unique inverse: \( f^{-1}(y) = \sqrt{\frac{y}{2}} \). The equation of the inverse of \( p(x) = \left(\frac{1}{2}\right)^{x} \) can be determined by swapping \( x \) and \( y \) and solving for \( y \). This gives us \( y = -\log_{1/2}(x) \), or more commonly \( p^{-1}(x) = -\log_2(x) \). This inverse exists because the original function is decreasing and one-to-one. For the function with the given inverse \( g^{-1}(x) = 2x - 4 \), we can find the equation of \( g(x) \) by swapping \( x \) and \( y \) and solving for \( y \). Start with \( x = 2y - 4 \), and rearranging gives us \( g(x) = \frac{x + 4}{2} \). So, \( g(x) = \frac{1}{2}x + 2 \) serves as the original function corresponding to the given inverse.