http://tieba.baidu.com/f?kz=1050970939帮解这条数学题!拜托!
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http://tieba.baidu.com/f?kz=1050970939帮解这条数学题!拜托!
http://tieba.baidu.com/f?kz=1050970939帮解这条数学题!拜托!
http://tieba.baidu.com/f?kz=1050970939帮解这条数学题!拜托!
稍微改变一下变量a点坐标(c,d);c点坐标(a,b),L1=e,d点坐标(x,y)
有方程组(a-x)²+(b-y)²=e²;(b-y)/(a-x)= - (c-x)/(d-y);
俩式展开a²-2ax+b²-2by+x²+y²=e²;x²+y²=x(a+c)+y(b+d)-ac-bd;
俩式相减,约去x²,y²,得到x关于y的表达式,带回方程组求解可知:
x=-(1/2/(-2*a*c-2*d*b+b^2+d^2+a^2+c^2)*(-2*e^2*b-4*a*c*b+2*d*e^2+2*b*a^2+2*d^2*b-
4*b^2*d+2*b^3+2*c^2*b+2*(6*a^2*c^2*e^2-e^4*a^2-e^4*c^2+2*e^4*a*c-2*e^2*b^2*a*c-
2*d*e^2*b*a^2-2*d*e^2*c^2*b+a^4*e^2+c^4*e^2+e^2*b^2*a^2+e^2*b^2*c^2+4*a*c*b*d*e^2-
4*a^3*c*e^2-4*a*c^3*e^2+d^2*e^2*a^2+d^2*c^2*e^2-2*d^2*a*c*e^2)^(1/2))*b-1/2/(-2*a*c-
2*d*b+b^2+d^2+a^2+c^2)*(-2*e^2*b-4*a*c*b+2*d*e^2+2*b*a^2+2*d^2*b-4*b^2*d+2*b^3+2*c^2*b+2*
(6*a^2*c^2*e^2-e^4*a^2-e^4*c^2+2*e^4*a*c-2*e^2*b^2*a*c-2*d*e^2*b*a^2-
2*d*e^2*c^2*b+a^4*e^2+c^4*e^2+e^2*b^2*a^2+e^2*b^2*c^2+4*a*c*b*d*e^2-4*a^3*c*e^2-
4*a*c^3*e^2+d^2*e^2*a^2+d^2*c^2*e^2-2*d^2*a*c*e^2)^(1/2))*d-a^2-b^2+e^2+a*c+d*b)/(a-c)
y=1/2/(-2*a*c-2*d*b+b^2+d^2+a^2+c^2)*(-2*e^2*b-4*a*c*b+2*d*e^2+2*b*a^2+2*d^2*b-
4*b^2*d+2*b^3+2*c^2*b+2*(6*a^2*c^2*e^2-e^4*a^2-e^4*c^2+2*e^4*a*c-2*e^2*b^2*a*c-
2*d*e^2*b*a^2-2*d*e^2*c^2*b+a^4*e^2+c^4*e^2+e^2*b^2*a^2+e^2*b^2*c^2+4*a*c*b*d*e^2-
4*a^3*c*e^2-4*a*c^3*e^2+d^2*e^2*a^2+d^2*c^2*e^2-2*d^2*a*c*e^2)^(1/2))
这四个角是不是直角?