如果4x-3是多项式4x2-1-5x+a的一个因式，则a等于（）。
A: -6
B: 6
C: -9
D: 9
A: -6
B: 6
C: -9
D: 9
举一反三
- 以4，9，1为为插值节点，求\(\sqrt x \)的lagrange的插值多项式 A: \( {2 \over {15}}(x - 9)(x - 1) + {3 \over {40}}(x - 4)(x - 1) + {1 \over {24}}(x - 4)(x - 9)\) B: \( - {2 \over {15}}(x - 9)(x - 1) + {3 \over {40}}(x - 4)(x - 1) + {1 \over {24}}(x - 4)(x - 9)\) C: \( - {2 \over {15}}(x - 9)(x - 1) + {3 \over {40}}(x - 4)(x +1) + {1 \over {24}}(x - 4)(x - 9)\) D: \( - {2 \over {15}}(x - 9)(x - 1) + {3 \over {40}}(x - 4)(x - 1) - {1 \over {24}}(x - 4)(x - 9)\)
- set1 = {x for x in range(10)} print(set1) 以上代码的运行结果为？ A: {0, 1, 2, 3, 4, 5, 6, 7, 8, 9} B: {0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10} C: {1, 2, 3, 4, 5, 6, 7, 8, 9} D: {1, 2, 3, 4, 5, 6, 7, 8, 9,10}
- 一随机变量X的E(X)=12, D(X)=9，用切比雪夫不等式估计P(6 A: 1/2 B: 2/3 C: 3/4 D: 4/5
- 函数\(y = {x^{ - 4}}{\rm{ + }}2{x^3} - 2x\)的导数为（ ）. A: \(4{x^3} + 6{x^2} - 2\) B: \( - 4{x^{ - 5}} + 6{x^2} - 2\) C: \( - 4{x^{ - 3}} + 6{x^2} - 2\) D: \( - 4{x^3} + 6{x^2} - 2\)
- 下面说法错误的是（ ）。知识点：列表推导式 A: dict([(x, x**2) for x in range(6)]) 创建的字典是{0: 0, 1: 1, 2: 4, 3: 9, 4: 16, 5: 25} B: [[x*3+y for y in range(1,4)] for x in range(3)] 创建的是二维列表 [[1, 2, 3], [4, 5, 6], [7, 8, 9]] C: number = [-2, 4, 6, -5]string = 'ab'z = [(i, j) if i>0 else (-i, j) for i in number for j in string]这段代码创建的列表为[(2, 'a'), (2, 'b'), (4, 'a'), (4, 'b'), (6, 'a'), (6, 'b'), (5, 'a'), (5, 'b')] D: ' '.join([i for i in range(1,11)])的运算结果为字符串'1 2 3 4 5 6 7 8 9 10'