- P(gun)]
Д(sh)W(xu)Ĺʽ
(do)Z(y)СҜ(zhn)ĸД(sh)W(xu)ҪĹʽȫϣ(du)gӭxHP(gun)֪R(sh)Ո(qng)P(gun)עCNFLAW(xu)(x)W(wng)!
˷cʽ a2-b2=(a+b)(a-b) a3+b3=(a+b)(a2-ab+b2) a3-b3=(a-b(a2+ab+b2)
Dzʽ |a+b|≤|a|+|b| |a-b|≤|a|+|b| |a|≤b<=>-b≤a≤b
|a-b|≥|a|-|b| -|a|≤a≤|a|
һԪη̵Ľ -b+√(b2-4ac)/2a -b-√(b2-4ac)/2a
cϵ(sh)`P(gun)ϵ X1+X2=-b/a X1*X2=c/a עf_(d)
Єeʽ
b2-4ac=0 עЃɂ(g)ȵČ(sh)
b2-4ac>0 עЃɂ(g)ȵČ(sh)
b2-4ac<0 ע̛](mi)Ќ(sh)йܗ(f)(sh)
Ǻ(sh)ʽ
ɽǺʽ
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-tanAtanB) tan(A-B)=(tanA-tanB)/(1+tanAtanB)
ctg(A+B)=(ctgActgB-1)/(ctgB+ctgA) ctg(A-B)=(ctgActgB+1)/(ctgB-ctgA)
ǹʽ
tan2A=2tanA/(1-tan2A) ctg2A=(ctg2A-1)/2ctga
cos2a=cos2a-sin2a=2cos2a-1=1-2sin2a
ǹʽ
sin(A/2)=√((1-cosA)/2) sin(A/2)=-√((1-cosA)/2)
cos(A/2)=√((1+cosA)/2) cos(A/2)=-√((1+cosA)/2)
tan(A/2)=√((1-cosA)/((1+cosA)) tan(A/2)=-√((1-cosA)/((1+cosA))
ctg(A/2)=√((1+cosA)/((1-cosA)) ctg(A/2)=-√((1+cosA)/((1-cosA))
Ͳe
2sinAcosB=sin(A+B)+sin(A-B) 2cosAsinB=sin(A+B)-sin(A-B)
2cosAcosB=cos(A+B)-sin(A-B) -2sinAsinB=cos(A+B)-cos(A-B)
sinA+sinB=2sin((A+B)/2)cos((A-B)/2 cosA+cosB=2cos((A+B)/2)sin((A-B)/2)
tanA+tanB=sin(A+B)/cosAcosB tanA-tanB=sin(A-B)/cosAcosB
ctgA+ctgBsin(A+B)/sinAsinB -ctgA+ctgBsin(A+B)/sinAsinB
ijЩ(sh)ǰn(xing)
1+2+3+4+5+6+7+8+9+…+n=n(n+1)/2 1+3+5+7+9+11+13+15+…+(2n-1)=n2
2+4+6+8+10+12+14+…+(2n)=n(n+1) 12+22+32+42+52+62+72+82+…+n2=n(n+1)(2n+1)/6
13+23+33+43+53+63+…n3=n2(n+1)2/4 1*2+2*3+3*4+4*5+5*6+6*7+…+n(n+1)=n(n+1)(n+2)/3
Ҷ a/sinA=b/sinB=c/sinC=2R ע R ʾεӈA돽
Ҷ b2=a2+c2-2accosB עB߅a߅cĊA
AĘ(bio)(zhn) (x-a)2+(y-b)2=r2 ע(a,b)LjA(bio)
Aһ㷽 x2+y2+Dx+Ey+F=0 עD2+E2-4F>0
タ(bio)(zhn) y2=2px y2=-2px x2=2py x2=-2py
ֱ(c)e S=c*h б(c)e S=c'*h
F(c)e S=1/2c*h' _(ti)(c)e S=1/2(c+c')h'
A_(ti)(c)e S=1/2(c+c')l=pi(R+r)l ıe S=4pi*r2
A(c)e S=c*h=2pi*h AF(c)e S=1/2*c*l=pi*r*l
L(zhng)ʽ l=a*r aLjAĽǵĻȔ(sh)r >0 eʽ s=1/2*l*r
Fwweʽ V=1/3*S*H AFwweʽ V=1/3*pi*r2h
бwe V=S'L ע,S'ֱe Lǂ(c)L(zhng)
wweʽ V=s*h Aw V=pi*r2h