Through reading extra-curricular books, I have accumulated a lot of knowledge

Through reading extra-curricular books, I have accumulated a lot of knowledge

Lack of subject
By reading extracurricular books, I have accumulated a lot of knowledge

After reading the article "reading for the rise of China", I received a profound education

The sentence lacks subject
After reading "reading for the rise of China", I received a profound education
or
After reading "reading for the rise of China", I received a profound education

What is the formula for the area and perimeter of a cone
Where R and L are to be explained

The side of the cone is expanded into a sector. If the generatrix length of the cone is l and the radius of the bottom circle is r, the expanded sector will have a radius of L and an arc length of 2 π R (that is, the circumference of the bottom circle). According to the sector area formula, the side area s = 1 / 2 * L * 2 π r = l π R

It is known that cosa = 3 / 5, and a belongs to [3 / 2 Wu, 2 Wu], cos (A-wu / 3)=

Cosa = 3 / 5, and a genus [3 / 2, 2]
∴sina=-4/5
We obtain (1 / 2) * cosa + (radical 3 / 2) Sina
, cos (A-wu / 3) = (3-4 radical 3) / 10

Solving equation 1) 5.2x-1.2x = 60 2) 8.7 (3.6-x) = 0 3) (38.5-x
Solving equation 1) 5.2x-1.2x = 60
2) 8.7(3.6-x)=0
3) (38.5-x-4.5)÷0.8=16

（1）5.2x-1.2x=4x4x=60x=60➗4x=15 （2）3.6-x=0➗8.73.6-x=0x=0+3.6x=3.6（3）38.5-x-4.5=16*0.838.5-x-4.5=12.838.5-x=12.8+4.538.5-x=17.317.3+38.5=xx=17.8+38.5x=56.3

It is known that the quadratic equation MX & sup2; - X-1 = 0 with respect to X has two unequal real roots

∵ two unequal roots of real numbers ∵ B & # 178; - 4ac ∵ 0 leads to 1 + 4m ∵ 0 ∵ m ∵ 1 / 4 and M = 0 is a one variable linear inequality ∵ m ≠ 0
∴m>-1/4 m≠0

If the two focuses and the two vertices of the minor axis of the ellipse are the four vertices of a diamond with a 60 ° angle, then the eccentricity of the ellipse is 0
The answer is 1 / 2 or root 3 / 2

E = C / a C = radical 3 * B a = 2 * B (analysis in a triangle composed of ABC)
Because the focus can be on the X or Y axis, there are two answers

(20-0.02) * (9.5 + 5) is there any clever calculation
The fastest bonus

(20-0.02)*(9.5+5)
=(20-0.02)*14.5
=20*14.5-0.02*14.5
=290-0.29
=289.71

Given that x = - 1 is a root of the equation x2-ax + 6 = 0, then a=______ ．

∵ x = - 1 is a root of the equation, ∵ - 1 can make both sides of the equation hold. Substituting x = - 1 into the equation is: (- 1) 2-A × (- 1) + 6 = 0, 1 + A + 6 = 0, a = - 7

The standard equation of hyperbola passing through point a (- 1, - 2) and having the same focus as ellipse x26 + Y29 = 1 is___ ．

∵ the focus of the ellipse x26 + Y29 = 1 is F1 (0, - 3), F2 (0, 3), ∵ the focus of the hyperbola is F1 (0, - 3), F2 (0, 3), let the hyperbolic equation be y2a2-x23-a2 = 1, substitute a (- 1, - 2), get 4a2-13-a2 = 1, get A2 = 2 or A2 = 6 (rounding), ∵ the standard equation of hyperbola is y22-x2 = 1. So the answer is y22-x2 = 1