[mathematics] when m is a value, y = MX ^ m & # 178; - 2m-1 is a quadratic function, and when x > 0, y decreases with the increase of X When m is the value, y = MX ^ m & # 178; - 2m-1 is a quadratic function, and x > 0, y decreases with the increase of X? Write the expression of the function, and answer whether the function has a maximum or a minimum? What is it? If the image of function y = ax & # 178; (a ≠ 0) passes through point (a, 1), then the value of a is ()

[mathematics] when m is a value, y = MX ^ m & # 178; - 2m-1 is a quadratic function, and when x > 0, y decreases with the increase of X When m is the value, y = MX ^ m & # 178; - 2m-1 is a quadratic function, and x > 0, y decreases with the increase of X? Write the expression of the function, and answer whether the function has a maximum or a minimum? What is it? If the image of function y = ax & # 178; (a ≠ 0) passes through point (a, 1), then the value of a is ()

m²＝2,
m＝±√2
When x > 0, y decreases with the increase of X
∴ m＜0
m＝﹣√2
∴ y＝﹣√2 x²＋2√2－1
The maximum value of Y is 2 √ 2-1
If the image of function y = ax & # 178; (a ≠ 0) passes through point (a, 1), then the value of a is (1)