Three pronunciations and word formation of "Cheng"

Ch è n
Weighing and praising
Weigh [ch è ng]: scale

What's the meaning of "forbidden"?

I can't help it
Pronunciation Q í ng B ù Z ì J ī n
Abstinence: restraint. Emotion is too excited to control oneself. Emphasis is completely controlled by some emotion
Liu Zun's poem "Qixi Chuanzhen" in the Southern Dynasty: "if you step on the moon intentionally, you can't help feeling."
She burst into tears again

Can't help doing sth

can’t help doing；can’t help doing sth.；can not help doing sth.

There are several ways to prove that space vectors are coplanar
Besides finding the sum of constants to be one, what else is there?

The mixed product is 0;
The determinant of order 3 is 0;
Find out the real numbers a, B, C which are not all zero so that ax + by + CZ = 0, where x, y, Z are vectors;
The normal vectors of any two planes determined by them are parallel

As shown in the figure, in the parallelogram, ∠ ABC = 75 °. AF ⊥ BC is in F, AF intersects BD in E, if de = 2Ab, ∠ AED=______ °．

Take the midpoint o of De, connect Ao, ∵ quadrilateral ABCD is a parallelogram, ∵ ad ∥ BC, ∵ DAB = 180 ° - ABC = 105 °, ∵ AF ⊥ BC, ∵ AF ⊥ ad, ∵ DAE = 90 °, ∵ OA = 12de = od = OE, ∵ de = 2Ab, ∵ OA = AB, ∵ AOB = ∵ ABO, ∵ ADO = ∵ Dao, ∵ AED = ∵ EAO, ∵ AOB

Who can solve math problems in grade three without equations
My father is 30 years old and my son is 5 years old. In a few years, my father will be twice as old as my son?
What is line drawing

(30-5)*2-30=20

1. A vector coordinate parallel to vector a = (1. - 3.2) is () a (1.3.2) B (- 1. - 3.2) C
1. A vector coordinate parallel to the vector a = (1. - 3.2) is () a (1.3.2) B (- 1. - 3.2) C (- 1.3.2) d (1. - 3. - 2) 2. If a tangent l of the fourth power of y = x is perpendicular to the straight line x + 4y-8 = 0, then the equation of L is? 3. If f (x) = xcos2x is known, then the inverse function f · (x) =? Is the final answer

1.-1,3,-2
2.y＝4x－3
3.cos2x－2xsin2x

In triangle ABC, angle a is equal to 120 degrees, ad bisects angle BAC, be bisects angle ABC, and calculates the degree of angle bed

The ∠ AEB is the outer angle of ∠ bed ∠ AEB = 180 ° - ∠ Abe - ∠ EAB ∫ BAC = 120 ° ad bisection ∠ BAC ∫ EAB = 60 ° (the size of ∠ ABC is not given, but ∠ Abe = 1 / 2 ∠ ABC can be obtained by the same principle), then ∠ AEB = 180 ° - ∠ Abe - ∠ EAB = 120 ° - 1 / 2 ∠ ABC (if △ ABC is an isosceles triangle, then ∠ Abe = 1

Given that the square of 2x + 3y-1 = 0, the value of the square of 2x + 6y-7 is zero

We know the square of 2x + 3y-1 = 0
2x²+3y=1
Square of 2x + 6y-7
=2(x²+3y)-7
=2*1-7
=-5

If points F1 and F2 are the focus of ellipse (x ^ 2 / 4) + y ^ 2 = 1, and P is the point on ellipse, when the area of △ f1pf2 is 1, the value of vector Pf1 and # 8226 is?

Ellipse: (X & # 178 / 4) + (Y & # 178 / 1) = 1
a²=4,b²=1,c²=3
a=2,b=1,c=√3
∴F1(-√3,0),F2(√3,0)
∴|F1F2|=2√3
The area of the triangle f1pf2 is 1
1=[（2√3)h]/2
h=(√3)/3
It also combines (X & # 178 / 4) + H & # 178; = 1
The result is: x = ± (2 √ 6) / 3
The coordinates of point P are (± (2 √ 6) / 3, ± √ 3 / 3)
∵{[(2√6)/3]-(-√3)}×{(√3)-[(2√6)/3]}=1/3=[(√3)/3]²
It can be seen from the projective theorem
∠F1PF2=90º
∴PF1*PF2=0

Three pronunciations and word formation of "Cheng"