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प्रश्न
Choose the correct alternative:
The solution of `("d"y)/("d"x) + x^2/y^2` = 0 is
विकल्प
x3 + y3 = 7
x2 + y2 = c
x3 + y3 = c
x + y = c
उत्तर
x3 + y3 = c
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संबंधित प्रश्न
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The rate of disintegration of a radioactive element at time t is proportional to its mass at that time. The original mass of 800 gm will disintegrate into its mass of 400 gm after 5 days. Find the mass remaining after 30 days.
Solution: If x is the amount of material present at time t then `dx/dt = square`, where k is constant of proportionality.
`int dx/x = square + c`
∴ logx = `square`
x = `square` = `square`.ec
∴ x = `square`.a where a = ec
At t = 0, x = 800
∴ a = `square`
At t = 5, x = 400
∴ e–5k = `square`
Now when t = 30
x = `square` × `square` = 800 × (e–5k)6 = 800 × `square` = `square`.
The mass remaining after 30 days will be `square` mg.
