CBSE Class 12 Math 2022 Term I Solved Paper

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Question : 17 of 50
 
Marks: +1, -0
The equation of the tangent to the curve y(1+x2) =2−x, where it crosses the X-axis is
Solution:
We have, equation of the curve y(1+x2)=2−x...(i)
∴y⋅(0+2x)+(1+x2)⋅dydx=0−1 [on differentiating w.r.t.x]
⇒2xy+(1+x2)dydx=−1
⇒dydx=−1−2xy1+x2... (ii)
Since, the given curve passes through x− axis i.e., y=0.
∴O(1+x2)=2−x [using Eq.(i)]
⇒x=2
So, the curve passes through the point (2,0).
∴(dydx)(2,0)=−1−2×01+22=−15= slope of the curve
∴ slope of tangent to the curve =−15
∴ Equation of tangent of the curve passing through (2,0) is
y−0=−15(x−2)
⇒5y=−x+2
⇒5y+x=2
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