Parabola: y

=

cut down on

*+

Bronx (Bronx)

+

c

a

& gt

At 0, the opening is upward a.

& lt

When it is 0, the opening is downward.

c

=

When the value is 0, the parabola passes through the origin.

b

=

0, the parabolic axis of symmetry is the y axis.

And vertex Y.

=

a(x+h)*

+

k

-h is x of vertex coordinates.

K is the y of vertex coordinates, which is generally used to find the maximum and minimum values.

Parabolic standard equation: y 2 = 2px

It means that the focus of the parabola is on the positive semi-axis of X, and the focal coordinate is (p/2,0).

The alignment equation is x=-p/2.

Since the focus of a parabola can be on any semi-axis, * * has a standard equation y 2 = 2px.

y^2=-2px

x^2=2py

x^2=-2py

the standard equation of the circle

(x-a)2+(y-b)2=r2

Note: (a, b) is the central coordinate.

Circular general equation

x2+y2+Dx+Ey+F=0

Note: D2+E2-4f > 0

Trigonometric function: the formula of the sum of two angles

sin(A+B)=sinAcosB+cosAsinB

sin(A-B)=sinAcosB-sinBcosA

cos(A+B)=cosAcosB-sinAsinB

cos(A-B)=cosAcosB+sinAsinB

tan(A+B)=(tanA+tanB)/( 1-tanA tanB)

tan(A-B)=(tanA-tanB)/( 1+tanA tanB)

cot(A+B)=(cotA cotB- 1)/(cot B+cotA)

cot(A-B)=(cotA cotB+ 1)/(cot b-cotA)

Double angle formula

tan2A=2tanA/( 1-tan2A)

cot2A=(cot2A- 1)/2cota

cos2a = cos2a-sin2a = 2 cos2a- 1 = 1-2 sin2a

sinα+sin(α+2π/n)+sin(α+2π* 2/n)+sin(α+2π* 3/n)+……+sin[α+2π*(n- 1)/n]= 0

cosα+cos(α+2π/n)+cos(α+2π* 2/n)+cos(α+2π* 3/n)+…+cos[α+2π*(n- 1)/n]= 0

and

sin^2(α)+sin^2(α-2π/3)+sin^2(α+2π/3)=3/2

tanAtanBtan(A+B)+tanA+tan B- tan(A+B)= 0