mx+my=m(x+y)
(a+b)2=a2+2ab+b2
(a-b)2=a2-2ab+b2
(a+b)(a-b)=a2-b2
(x+a)(x+b)=x2+(a+b)x+ab
ax2+bx+c=0のとき
x=(-b±√b2-4ac)/2a
S=πr2
π:円周率 r:円の半径
S=4πr2
π:円周率 r:球の半径
V=4/3πr3
π:円周率 r:球の半径
(x-a)2+(y-b)2=r2
a.b:円の中心の座標 r:円の半径
sin(α+β)=sinαcosβ+cosαsinβ
sin(α-β)=sinαcosβ-cosαsinβ
cos(α+β)=cosαcosβ-sinαsinβ
cos(α-β)=cosαcosβ+sinαsinβ
tan(α+β)=(tanα+tanβ)/1-tanαtanβ
tan(α-β)=(tanα-tanβ)/1+tanαtanβ
tanθ=sinθ/cosθ
sin2θ+cos2θ=1
sin2θ=(1-cos2θ)/2
cos2θ=(1+cos2θ)/2
y=xn → dy/dx=nxn-1
y=sinx → dy/dx=cosx
y=cosx → dy/dx=-sinx
y=tanx → dy/dx=1/cos2x
kは比例定数
y=xn → ∫ydx=xn+1/n+1 +k
y=sinx → ∫ydx=-cosx +k
y=cosx → ∫ydx=sinx +k
y=εx → ∫ydx=εx +k