WAEC - Further Mathematics (2017 - No. 7)
Given that \(f(x) = \frac{x+1}{2}\), find \(f^{1}(-2)\).
-5
-3
\(-\frac{1}{2}\)
5
คำอธิบาย
Let \(f(x) = y\), then we have
\(y = \frac{x+1}{2} \implies 2y = x+1; x = 2y-1\)
Let \(f^{1}(x) = x; x = 2y-1\), replacing y with x,
\(f^{1}(x) = 2x - 1 \implies f^{1}(-2) = 2(-2) -1= -5\)