If 2 x y + 3 y x = 20 , then d y d x at 2 , 2 is equal to:

If 2xy+3yx=20, then dydx at 2,2 is equal to:
  1. -2+loge83+loge4
  2. -3+loge164+loge8
  3. -3+loge82+loge4
  4. -3+loge42+loge8

Solution

Given,

2xy+3yx=20

Now differentiating both sides w.r.t x, we get

2xyy'lnx+yx+3yxlny+xy·y'=0 here ln=loge

Putting x=2 & y=2, we get

8ln2·y'+1+12lny+y'=0

8ln2·y'+1+12lny+y'=0

y'=-3ln2+22ln2+3

y'=-2+ln83+ln4

Asked in: JEE Main 2023 (06 Apr Shift 1)

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