Find the equation of a curve passing through (2, 1) if the slope of the tangent to the curve at any point (x, y) is
Slope of tangent is given as
Slope of tangent of a curve y = f(x) is given by
Put y = vx
Differentiate vx using product rule,
Integrate
Put 1 – v2 = t hence differentiating with respect to v we get which means 2vdv = -dt
Resubstitute t
Resubstitute v
Now it is given that the curve is passing through (2, 1)
Hence (2, 1) will satisfy the curve equation (a)
Putting values x = 2 and y = 1 in (a)
Using log a + log b = loga b
Put c in equation (a)
Using log a – log b = log
Using log a + log b = log ab
⇒ 3x = 2(x2 – y2)
⇒ 3x = 2x2 – 2y2
⇒ 2y2 = 2x2 – 3x
Hence equation of curve is