一道SAT2数学题答好了我加分 if f(x)=x³-4x²-3x+2 which of the following are true?1.the function f is increasing for x≥32.the equation f(x)=o has two nonreal solutions3.f(x)≥-16 for all x≥0答案是1和3,为什么2不对?1,3
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![一道SAT2数学题答好了我加分 if f(x)=x³-4x²-3x+2 which of the following are true?1.the function f is increasing for x≥32.the equation f(x)=o has two nonreal solutions3.f(x)≥-16 for all x≥0答案是1和3,为什么2不对?1,3](/uploads/image/z/10055043-27-3.jpg?t=%E4%B8%80%E9%81%93SAT2%E6%95%B0%E5%AD%A6%E9%A2%98%E7%AD%94%E5%A5%BD%E4%BA%86%E6%88%91%E5%8A%A0%E5%88%86+if+f%28x%29%3Dx%26%23179%3B-4x%26%23178%3B-3x%2B2+which+of+the+following+are+true%3F1.the+function+f+is+increasing+for+x%E2%89%A532.the+equation+f%28x%29%3Do+has+two+nonreal+solutions3.f%28x%29%E2%89%A5-16+for+all+x%E2%89%A50%E7%AD%94%E6%A1%88%E6%98%AF1%E5%92%8C3%2C%E4%B8%BA%E4%BB%80%E4%B9%882%E4%B8%8D%E5%AF%B9%3F1%2C3)
一道SAT2数学题答好了我加分 if f(x)=x³-4x²-3x+2 which of the following are true?1.the function f is increasing for x≥32.the equation f(x)=o has two nonreal solutions3.f(x)≥-16 for all x≥0答案是1和3,为什么2不对?1,3
一道SAT2数学题
答好了我加分 if f(x)=x³-4x²-3x+2 which of the following are true?
1.the function f is increasing for x≥3
2.the equation f(x)=o has two nonreal solutions
3.f(x)≥-16 for all x≥0
答案是1和3,为什么2不对?1,3又是怎么算出来的?
一道SAT2数学题答好了我加分 if f(x)=x³-4x²-3x+2 which of the following are true?1.the function f is increasing for x≥32.the equation f(x)=o has two nonreal solutions3.f(x)≥-16 for all x≥0答案是1和3,为什么2不对?1,3
f(x)=x³-4x²-3x+2
f'(x)=3x²-8x-3>=0
(3x+1)(x-3)>=0
x=3时导数>=0,即为函数递增区间,即
1.the function f is increasing for x≥3,正确.
2.因为f(-1)=-1-4+3+2=0
x=-1是一实数解;
f(0)=2,f(2)=8-16-6+2=-12=0
f'(x)=3x²-8x-3>=0
(3x+1)(x-3)>=0
x在[0,3),导数0,函数递增,
所以
x=3为最小值点,此时取最小值f(3)=3³-4*3²-3*3+2=27-36-9+2=-16
从而
f(x)≥-16 for all x≥0.
正确!
答案是1和3,没错!
3.14*3^2*6-6^2/2*6 先看一下题意:正方体棱柱内切与一个圆柱内。也就是说棱柱的底面是正方形,正方形内切与圆柱。知道圆柱底面的半径是3,
2、你可以拆分函数,设g(x)=x^3 h(x)=-4x^2-3x+2 画出两个函数的大致图像,在定义域内看有几个交点,就有几个解。
1、求函数的增区间,你可以带入x和x+1,然后f(x)
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2、你可以拆分函数,设g(x)=x^3 h(x)=-4x^2-3x+2 画出两个函数的大致图像,在定义域内看有几个交点,就有几个解。
1、求函数的增区间,你可以带入x和x+1,然后f(x)
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