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Parallelogram rule how to use ah, seeking method
The rules of parallelogram are: opposite sides parallel and equal, diagonal equal, adjacent complementary, diagonal bisection, etc.; as for how to use, it depends on you to do more questions
The number corresponding to point a on the number axis is - 5. Point B is on the right side of point A. electronic ant a and B move to the left at the speed of 2 units per second and 1 unit per second respectively at point B / electronic ant C move to the right at the speed of 3 units per second at point a
If the electron moves to point C after 5 seconds, find the number of point C
They set out at the same time. If C meets B one second after meeting a, find the representation of B
Under the condition of 〈 2 〉, let them start at the same time in T seconds. Is there a value of T, so that the distance between C and B is twice the distance between C and a? If there is, find the value of T. if not, explain the reason
1) C moved: 5 * 3 = 15 units
Then c means - 5 + 15 = 10
2) Let the number represented by B be x, then AB distance X - (- 5) = x + 5 units
Meeting time of a and C: (x + 5) / (3 + 2) = (x + 5) / 5
Meeting time: (x + 5) / (3 + 1) = (x + 5) / 4
The equation is: (x + 5) / 4 - (x + 5) / 5 = 1
The solution is x = 15
So B means 15
3. Assuming the existence, the distance between C and B is: (x + 5) - t (1 + 3) = 20-4t
Distance between a and C: (x + 5) - t (2 + 3) = 20-5t
20-4t=(20-5t)*2
The solution is t = 10 / 3
The meeting time of a and C is: 20 / 5 = 4
10/3
If three points a (- 2, - 3), B (19,4), C (- 1, - 6) are known, then what triangle ABC is
The slope of line AC KAC = (- 3 + 6) / (- 2 + 1) = - 3
The slope of segment BC is KBC = (4 + 3) / (19 + 2) = 7 / 21 = 1 / 3
∵Kac*Kbc=-3*1/3=-1
The AC is perpendicular to the BC
A triangle ABC is a right triangle
Calculus: F (x) is a continuous function with period T
When x approaches infinity, the limit of [1 / x times the integral of F (T) on (0, x)] is equal to 1 / T times the integral of F (T) on (0, t)
In my answer, the paragraphs beginning with "(") are all my explanation of a certain step or solution idea. I think it can help you understand the practice of this kind of problem, so I wrote, if you don't need it, you can not read it, because f has a period, so the integral of F on (NT, (n + 1) t) is the same for every integer n
What is the operation law of addition and subtraction
When learning addition in the first grade, I once discussed the rule that "adding two numbers can exchange the position of two addends, and the number will not change" in combination with the real situation, but I didn't discuss the law of combination of addition. In the first section, there are no concepts such as the law of exchange of addition and the law of combination of addition, so how to explain the calculation of addition or subtraction
Finding the n-order derivative of y = sin3x * sin2x
y(1)=6cos3xcos2x
y(2)=6^2*sin3xsin2x
When n is odd, y (n) = 6 ^ n * cos3xcos2x;
When n is even, f (n) = 6 ^ n * sin3xcos2x
How to teach addition and subtraction in grade one
Practice the ten methods first
1+9=10
2+8=10
8+2=10
9+1=10
I've memorized all these!
In the system of equations {2x + 3Y = M-1 3x + 2Y = 3M, if the unknown x y satisfies x + Y > 0, then the value range of M?
A M＞1
B M > 3 / 2
C M > quarter
D M < quarter
2x+3y=m-1 (1)
3x+2y=3m (2)
(1) + (2) get
5x+5y=4m-1
x+y=(4m-1)/5
x +y>0
∴(4m-1)/5>0
m>1/4
Choose C
The seven numbers 0-6 make up a formula that one digit multiplied by one digit equals one digit, and two digits divided by one digit equals one digit
2 times 3 equals 6.. 5 divided by 14 equals 0, the remainder is not considered
As shown in the figure, it is known that the intersection of the straight line y = X-2 and the hyperbola y = KX (x > 0) is at point a (3, m). (1) find the value of M, K; (2) connect OA, whether there is a point Q on the positive half axis of X axis, so that △ AOQ is an isosceles triangle? If it exists, please write directly the coordinates of all qualified points Q; if it does not exist, please explain the reason
(1) ∵ point a (3, m) on the straight line y = X-2 ∵ M = 3-2 = 1 ∵ the coordinates of point a are (3, 1) ∵ point a (3, 1) on the hyperbola y = KX ∵ 1 = K3 ∵ k = 3 (2) ∵ if OA = OQ, then Q1 (10, 0); if OA = AQ, then Q2 (6, 0); if OQ = AQ, then Q3 (53, 0) ∵ Q1 (10, 0)
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