试题与答案

曲线y=2x2在点P(1,2)处的切线方程是( ) A.4x-y-2=0 B.4

题型:选择题

题目:

曲线y=2x2在点P(1,2)处的切线方程是(  )

A.4x-y-2=0

B.4x+y-2=O

C.4x+y+2=O

D.4x-y+2=0

答案:

∵曲线y=2x2过点P(1,2)

∴y′=4x,在点x=1斜率k=4×1=4,

∴y=2x2在点P(1,2)处的切线方程是:y-2=4(x-1),

∴4x-y-2=0,

故选A.

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