MHT CET202013 Oct 2020Evening ShiftMathematicsApplication of DerivativesActual

If the line 6 x-y-4=0 touches the curve y²=a x³+b at the point (1,2) then a+b=

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Correct answer

C. 4

Step-by-step solution

Slope of line 6 x-y-4=0 is 6 and this line is tangent to the curve y²=a x³+b at point (1,2) 2 y d y d x =3 a x² ( d y d x )_ (1,2) = 3 a x² 2 y = 3 a 4 and 3 a 4 =6 a=8 Now point (1,2) lies on given curve. (2)²=(8)(1)³+b b=-4 a+b=8-4=4

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