Ladies and gentlemen, please help my little brother to send high school math formulas, thank you

1.Induction formula.

sin(-a)=-sin(a)

cos(-a)=cos(a)

sin(π2-a)=cos(a)

cos(π2-a)=sin(a)

sin(π2+a)=cos(a)

cos(π2+a)=-sin(a)

sin(π-a)=sin(a)

cos(π-a)=-cos(a)

sin(π+a)=-sin(a)

cos(π+a)=-cos(a)

2.Trigonometric function of the sum and difference of two angles.

sin(a+b)=sin(a)cos(b)+cos(α)sin(b)

cos(a+b)=cos(a)cos(b)-sin(a)sin(b)

sin(a-b)=sin(a)cos(b)-cos(a)sin(b)

cos(a-b)=cos(a)cos(b)+sin(a)sin(b)

tan(a+b)=tan(a)+tan(b)1-tan(a)tan(b)

tan(a-b)=tan(a)-tan(b)1+tan(a)tan(b)

3.and the difference product formula.

sin(a)+sin(b)=2sin(a+b2)cos(a-b2)

sin(a)−sin(b)=2cos(a+b2)sin(a-b2)

cos(a)+cos(b)=2cos(a+b2)cos(a-b2)

cos(a)-cos(b)=-2sin(a+b2)sin(a-b2)

4.Double angle formula.

sin(2a)=2sin(a)cos(b)

cos(2a)=cos2(a)-sin2(a)=2cos2(a)-1=1-2sin2(a)

5.Half-angle formula.

sin2(a2)=1-cos(a)2

cos2(a2)=1+cos(a)2

tan(a2)=1-cos(a)sin(a)=sina1+cos(a)

6.Magna formula.

sin(a)=2tan(a2)1+tan2(a2)

cos(a)=1-tan2(a2)1+tan2(a2)

tan(a)=2tan(a2)1-tan2(a2)

7.Other formulas (derived).

a sin(a)+b cos(a)=a2+b2sin(a+c) where tan(c)=ba

a sin(a)+b cos(a)=a2+b2cos(a-c) where tan(c)=ab

1+sin(a)=(sin(a2)+cos(a2))2

1-sin(a)=(sin(a2)-cos(a2))2

Electrician: UAB=UA-UB, UBA=UB-UA, because UA-UB=- (UB-UA), so UAB=-UBA.

The notation of voltage is directional. If the current flows from A to B, the potential of point A is higher than that of point B, and the voltage UAB=UA-UB is a positive value; Conversely, the voltage from B to A is a negative value. uab=-uba。

3-2-2 = (2) 2-2+1 = (2-1), and 2-1 = 1 (2+1).

So the value is evaluated as a 2

You can go to the bookstore and buy it, a book card, collect all the high school math formulas, five dollars a piece, and it is sold in bookstores large and small.

Buy a booklet.

It's very complete inside.