WAEC - Mathematics (1991 - No. 10)
Simplify: \(\frac{1}{4}(2^n - 2^{n + 2}\))
\(2^{n - 2} - 2^n\)
\(2^{n-2}(1-2^n\))
\(2^n + 2^{2 + n}\)
\(2^{2n}\)
คำอธิบาย
\(\frac{1}{4}(2^n - 2^{n + 2}\)) = \(\frac{1}{4}(2^n - 2^n \times2^2\))
\(\frac{1}{4} \times2^n(1 - 2^2\)) = \(2^{-2}\times2^n(1 - 2^2\))
\(2^{n - 2}(2^0 - 2^2\)) = \(2^{n - 2} - 2^n\)