画圈圈的这几道题.
来源:学生作业帮 编辑:搜搜做题作业网作业帮 分类:数学作业 时间:2024/07/14 13:48:55
画圈圈的这几道题.
![](http://img.wesiedu.com/upload/3/a4/3a4d13685f70a5a6b3317b83f5246509.jpg)
![](http://img.wesiedu.com/upload/3/a4/3a4d13685f70a5a6b3317b83f5246509.jpg)
![画圈圈的这几道题.](/uploads/image/z/16508319-15-9.jpg?t=%E7%94%BB%E5%9C%88%E5%9C%88%E7%9A%84%E8%BF%99%E5%87%A0%E9%81%93%E9%A2%98.%26nbsp%3B)
5. 1
f(x)=sinx-cosx > 0 x∈[π/4,3π/4]
S=∫[π/4→3π/4](sinx-cosx)dx=(-cos3π/4-sin3π/4)-(-cosπ/4-sinπ/4)=(1/2-1/2)-(-1/2-1/2)=1
6. 8π
y²=4(1-x²/9), y=0,x>0则x=3
V=∫[0→3]πy²dx=∫[0→3]4π*(1-x²/9)dx=4π*[(3-3³/27)-0]=8π
8. exp(1)-3/2
A={y=exp(x)∩y=-x+1}, A={(0,1)} →exp(x)>-x+1 (x>0)
B={y=exp(x)∩x=1}, B={(1,exp(1)}
C={x=1∩y=-x+1}, C={(1,0)}
S=∫[0→1](exp(x)-(-x+1))dx=(exp(1)+1/2-1)-(exp(0)+0-0)=exp(1)-3/2
9. 36
s=∫[0→3]vdt=∫[0→3](3t²+2t)dt=(3³+3²)-(0³+0²)=36
f(x)=sinx-cosx > 0 x∈[π/4,3π/4]
S=∫[π/4→3π/4](sinx-cosx)dx=(-cos3π/4-sin3π/4)-(-cosπ/4-sinπ/4)=(1/2-1/2)-(-1/2-1/2)=1
6. 8π
y²=4(1-x²/9), y=0,x>0则x=3
V=∫[0→3]πy²dx=∫[0→3]4π*(1-x²/9)dx=4π*[(3-3³/27)-0]=8π
8. exp(1)-3/2
A={y=exp(x)∩y=-x+1}, A={(0,1)} →exp(x)>-x+1 (x>0)
B={y=exp(x)∩x=1}, B={(1,exp(1)}
C={x=1∩y=-x+1}, C={(1,0)}
S=∫[0→1](exp(x)-(-x+1))dx=(exp(1)+1/2-1)-(exp(0)+0-0)=exp(1)-3/2
9. 36
s=∫[0→3]vdt=∫[0→3](3t²+2t)dt=(3³+3²)-(0³+0²)=36