1. The monotone interval of function y = x ^ 4-4x ^ 2-5 is? 1. Find the monotone interval and extremum of function y = x ^ 3-x ^ 2-x + 1? I want to explain, because the foundation is not very good, many do not understand

1. The monotone interval of function y = x ^ 4-4x ^ 2-5 is? 1. Find the monotone interval and extremum of function y = x ^ 3-x ^ 2-x + 1? I want to explain, because the foundation is not very good, many do not understand


① Because y = x ^ 4-4x ^ 2-5, so y '= 4x ^ 3-8x, let y' = 4x ^ 3-8x = 0 get: x = 0 or ± root 2. From the list, we can see that the monotone increasing intervals of y = x ^ 4-4x ^ 2-5 are: (- root 2,0) and (root 2, + infinity), and the monotone decreasing intervals of Y are: (- infinity, - root 2) and
(0, root 2)
② Because y = x ^ 3-x ^ 2-x + 1, so y '= 3x ^ 2-2x-1, let y' = 3x ^ 2-2x-1 = 0 get: x = 1 or - 1 / 3, the list shows that the monotone increasing interval of y = x ^ 3-x ^ 2-x + 1 is: (- infinite, - 1 / 3) and (1, + infinite), and the monotone decreasing interval of Y is: (- 1 / 3,1), so
Y gets the maximum at x = - 1 / 3: y = f (- 1 / 3) = 32 / 27, y gets the minimum at x = 1: y = f (1) = 0



In the plane coordinate system, O is the coordinate origin, take a point P on the image of the function y = – 3x, pass through the point P as the PA ⊥ X axis, the abscissa of the known point P is – 2, and calculate the area of the triangle POA


Take - 2 into y = - 3x to get PA = 6, and then solve it according to the triangle area formula, that is, s = 1 / 2PA × OA



Take a point P on the image of the function y = - 3, and make the PA ⊥ X axis through the P point. Given that the coordinate of P point is - 2, it is necessary to find the area of △ POA (o is the origin of the coordinate)


Because PA = 3, Ao = 2, this is a right triangle, PA Ao is a right side, so s = PA * AO * 1 / 2 = 3



Let f (x) be continuous in the closed interval [0.1] and differentiable in [0.1], f (0) = 0, f (1) = 1. It is proved that there exists ξ ε (0,1) such that f (ξ) + F '(ξ) = 0


F (1) = 0. Constructor f (x) = f (x) e ^ x, Rolle theorem, f '(ξ) = 0. Simplification is the answer



To do the mixed operation of addition and subtraction of rational numbers, we first unify the subtraction into method, and then use the sum of method to carry out the operation, that is, a + B-C = a + B + (- C)


To do the mixed operation of addition and subtraction of rational numbers, first the subtraction is unified into addition, and then the operation is carried out by using the commutative law and associative law of addition, i.e. a + B-C = a + B + (- C)



Given a = (5 √ 3cosx, cosx), B = (SiNx, 2cosx), Let f (x) = a · B + | B | ^ 2-1 / 2
1. When - π / 6 ≤ x ≤ π / 4, find the range of function f (x)
2. In (1), when the function f (x) is the maximum, we find the minimum value of | 2A / t-tb | (t ∈ R and t ≠ 0)


F (x) = AB + | B | ^ 2-1 / 2 = 5 √ 3cosxsinx + 2 (cosx) ^ 2 + (SiNx) ^ 2 + 4 (cosx) ^ 2-1 / 2 = (5 √ 3 / 2) sin2x + 6 (1 + cos2x) / 2 + (1-cos2x) / 2-1 / 2 = (5 √ 3 / 2) sin2x + (5 / 2) cos2x + 3 = 5sin (2x + π / 6) + 3 - π / 6 ≤ x ≤ π / 4, - π / 6 ≤ 2x + π / 6 ≤ 2 π / 3 F (x) in 2



What is abdication addition and subtraction


31-8 = 13
Subtraction starts from the low, 1 minus 8, if not enough, borrow 1 from the ten, that is, a ten, so that 11-8 = 3
At this time, the 3 on the 10th bit becomes 2, that is, the 3 on the original 10th bit takes out 1 and retreats to one bit to participate in the calculation. In this way, the 10th bit is 2, so 31-8 = 23, which is abdication minus



Given that the solutions X and y of the equations 2x + y = a + 1, x-2y = 3a-2 are positive numbers, then the value range of a is?


Solve the equations {2x + y = a + 1, x-2y = 3a-2
The solution is: {x = a, y = 1-A
∵ X and y are positive numbers
∴a>0,1-a>0
∴0



In the case of 123456789 nine numbers, the formula is established. One four digit number multiplied by one digit equals another four digit number. The number can not be repeated


1738 * 4 = 6952
1963 * 4 = 7852



A of right angle △ AOB is the intersection of hyperbola y = K / X and straight line y = - X - (K + 1) in the second quadrant. Ab ⊥ X axis is in B, and △ AOB area is 3 / 2
(1) If there are two intersections A and C between the straight line and the hyperbola, and the abscissa of a and the ordinate of C are - 1, the coordinates of a and C and the area of △ AOC can be obtained. O is the coordinate origin


1) K / x = - X - (K + 1) x ^ 2 + (K + 1) x + k = 0 (x + 1) (x + k) = 0x1 = - 1, X2 = - K is in the second quadrant, so the abscissa of K0, a is X1 = - 1, ordinate = K / - 1 = - Ka (- 1, - K) B (- 1,0) △ AOB area = AB * Bo / 2 = k * 1 / 2 = K / 2, and △ AOB area = 3 / 2, so K / 2 = 3 / 2K = 3. These two functions are: y = 3 / xy = - X -