Re: [微分] 切線問題
※ 引述《di7101483 (新生代)》之銘言：
: Find the points on the graph of y=x^5/3+x^1/3 at which the tangent line is
: perpendicular to the line 2y+x=7
: 這題的方程式怎麼那麼難解
y'=5/3*x^(2/3)+1/3*x(-2/3) = 2
5x^(2/3)+x^(-2/3)=6
令x^(2/3)=z
:5z+1/z=6
5z^2-6z+1=0
(5z-1)(z-1)=0
z=1/5,1
x=5^(-3/2), 1
y=26根號5/125, 2
(5^(-3/2),26根號5/125) , (1,2)
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※ 編輯: a88241050 來自: 140.135.32.98 (12/06 17:40)
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