In the long jump competition, Xiao Ming jumped 3 meters, Xiao Ming's 56 is equal to Xiao Jun's, Xiao Li's 45. How many meters did Xiao Jun and Xiao Li jump?

In the long jump competition, Xiao Ming jumped 3 meters, Xiao Ming's 56 is equal to Xiao Jun's, Xiao Li's 45. How many meters did Xiao Jun and Xiao Li jump?

3 × 56 = 2.5 meters; 3 × 45 = 2.4 meters; a: Xiaojun and Xiaoli jumped 2.5 meters and 2.4 meters respectively

3. It took Xiaojun five minutes to ride a bicycle from home to school. At the same speed, he rode from school to the library
450 meters from home to school
School to library y meters
Use a formula with letters to express the time Xiaojun takes from home to the library

It can be calculated that the riding speed of Xiaojun is 450 △ 5 = 90 m / min, and the time from home to the library is 5 + y △ 90 min, which is expected to be adopted

What is the result of integrating x to the x ^ 2 power of E?

∫e^（x^2）dx
=xe^（x^2）-∫xe^（x^2）dx
=xe^（x^2）-1/2∫e^（x^2）dx^2
=xe^（x^2）-1/2e^（x^2）+c
=（x-1/2）e^（x^2）+c

We know that O is the outer center of the triangle ABC, ab = 2, AC = 3, x + 2Y = 1,
It is known that O is the outer center of the triangle ABC, ab = 2, AC = 3, x + 2Y = 1. If the vector Ao = x vector AB + y vector AC, (XY is not zero), then the cosine value of the angle BAC is
Let's see tomorrow

Let d be the midpoint of the AC side,
Vector Ao = x vector AB + y vector AC, (omit the word vector below)
1*AO=x(OB-OA)+y(OC-OA)
That is, (x + 2Y) Ao = x (ob-oa) + y (oc-oa)
The results show that xob = - Y (OA + OC)
Therefore, OB and OA + OC are collinear,
OB and od are collinear,
Because o is the outer center, so | OA | = | OC|
And D is the midpoint of AC,
So OD ⊥ AC,
OB and OD collinear (proved)
So, BD ⊥ AC
So cos ∠ BAC = ad / AB = 1.5 / 2 = 0.75

What is the relationship between limit and derivative?

Derivative is defined on the basis of limit. If there is no limit, there will be no derivative! Then derivative in turn can calculate some special limits, such as lobita's law, Taylor's theorem and so on!

The solution equation: 5x = 0.3, 8.4 + x = 10

x=0,06 x=1,6

Solution inequality - x ^ 2 + 4x + 5 > = 0, and solution set

(x-5)(x+1)

What is arctan-1 equal to

arctan-1=-π/4
I'm a teacher. Thank you

Given that one root of the equation x ^ 2-bx + 2 = 0 is 2, find another root and the value of B

x^2-bx+2=0
So X1 + x2 = B
x1x2=2
x1=2
So x2 = 1
b=x1+x2=3

If the constant term in the binomial (AX2 + 1x) 5 expansion is 5, then the real number a=______ ．

The general term formula of the expansion of binomial (AX2 + 1x) 5 is tr + 1 = Cr5 · & nbsp; A5 − R & nbsp; · & nbsp; X10 − 2R & nbsp; · & nbsp; X & nbsp; − R2 = Cr5 · & nbsp; A5 − R & nbsp; · & nbsp; X10 − 52r, let 10-5r2 = 0, then r = 4, so the constant term in the expansion is C15 · & nbsp