✔ 最佳答案
1.積分 1到-1 (絕對值x^3)dx
Sol
∫(1 to -1)_|x^3|dx
=∫(1 to 0)_|x^3|dx+∫(0 to -1)_|x^3|dx
=∫(1 to 0)_x^3dx+∫(0 to -1)_-x^3dx
=x^4/4|(1 to 0)-x^4/4|(0 to -1)
=(0-1/4)-(1/4-0)
=-1/2
2.曲線 y^2=4x 和 x+y+2=0 的最短距離
Sol
y^2=4x 上一點 (a,b)
L=|a+b+2|/√2
2L^2=(a+b+2)^2
32L^2=(4a+4b+8)^2=(b^2+4b+8)^2=[(b+2)^2+4]^2
p=最短距離
32p^2=16
p^2=1/2
p=√2/2
3.f (x)=Sin^2 x-2Cosx+2之最大值
Sol
Sin^2 x-2Cosx+2
=1-Cos^2 x-2Cosx+2
=-(Cos^2x+2Cosx)+3
=-(Cos^2x+2Cosx+1)^2+4
=-(Cosx-1)^2+4
-1<=Cosx<=1
-1-1<=Cosx-1<=0
-2<=Cosx-1<=0
0<=(Cosx-1)^2<=4
-4<=-(Cosx-1)^2<=0
0<=-(Cosx-1)^2<=4
最大值=4
4.4y^2=(2x +1)^2+9的漸近線
Sol
4y^2=(2x +1)^2+9
4y^2-4(x +1/2)^2=9
漸近線
4y^2-4(x+1/2)^2=0
(2y-2x-1)(2y+2x+1)=0
(2x-2y+1)(2x+2y+1)=0
兩漸近線
2x-2y+1=0 和 2x+2y+1=0