y=(x²+16)/((根号x²)+4)的最小值为
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![y=(x²+16)/((根号x²)+4)的最小值为](/uploads/image/z/4003456-40-6.jpg?t=y%3D%28x%26%23178%3B%2B16%29%2F%28%28%E6%A0%B9%E5%8F%B7x%26%23178%3B%29%2B4%29%E7%9A%84%E6%9C%80%E5%B0%8F%E5%80%BC%E4%B8%BA)
y=(x²+16)/((根号x²)+4)的最小值为
y=(x²+16)/((根号x²)+4)的最小值为
y=(x²+16)/((根号x²)+4)的最小值为
y=(x^2+16)/(√x^2+4)
= (x^2-16+32)/(√x^2+4)
=[(√x^2+4)(√x^2-4)+32]/(√x^2+4)
=(√x^2-4)+32/(√x^2+4)
=(√x^2+4)+32/(√x^2+4)-8
>=2√(√x^2+4)*32/(√x^2+4)-8=8√2-8
即y的最小值为8√2-8