...x²-y²),(3,1)(lemniscate)隐函数问题求切线方程
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发布时间:2024-05-14 19:37
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时间:2024-05-28 14:19
2(x²+y²)²=25(x²-y²)
x0=3,y0=1
两边同时对x求导:
2*2(x²+y²)*(2x+2y*y′) = 25*(2x-2y*y′)
即,4(x²+y²)*(x+y*y′) = 25*(x-y*y′)
将x0=3,y0=1代入上式等:
4*(3²+1²)*(3+y0′) = 25*(3-y0′)
8*(3+y0′) = 5*(3-y0′)
24+8y0′ = 15-5y0′
13y0′ = -9
切线斜率 = y0′ = -9/13
切线:y-1 = -9/13(x-3)
即,9x+13y-40=0