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If dy/dx = x - y2 and y(0) = 1, then y(0.1) correct upto two decimal places (approx.) is:
  • a)
    0.85
  • b)
    0.84
  • c)
    0.91
  • d)
    1.01
Correct answer is option 'B'. Can you explain this answer?
Most Upvoted Answer
Ifdy/dx = x - y2 and y(0) = 1, then y(0.1) correct upto two decimal pl...
Given:
$\frac{dy}{dx} = x - y^2$
$y(0) = 1$

To Find:
$y(0.1)$ correct up to two decimal places.

Explanation:
To solve this differential equation, we can use the method of separation of variables.

Separating the variables, we get:
$\frac{dy}{1-y^2} = x \, dx$

Integration:
Integrating both sides with respect to their respective variables, we get:
$\int{\frac{dy}{1-y^2}} = \int{x \, dx}$

LHS Integration:
To integrate the left-hand side, we can use partial fraction decomposition. The general form of the partial fraction decomposition is:
$\frac{A}{y-1} + \frac{B}{y+1}$

Multiplying through by the common denominator $(y-1)(y+1)$, we get:
$1 = A(y+1) + B(y-1)$

Expanding and equating the coefficients of like terms, we get:
$1 = (A + B)y + (A - B)$

Comparing the coefficients of 'y', we get:
$A + B = 0 \implies A = -B$

Comparing the constants, we get:
$A - B = 1$

Solving these equations, we find:
$A = \frac{1}{2}$ and $B = -\frac{1}{2}$

Substituting these values back into the partial fraction decomposition, we get:
$\frac{\frac{1}{2}}{y-1} - \frac{\frac{1}{2}}{y+1}$

Integrating each term separately, we get:
$\frac{1}{2}\ln|y-1| - \frac{1}{2}\ln|y+1|$

RHS Integration:
Integrating the right-hand side, we get:
$\int{x \, dx} = \frac{x^2}{2} + C_1$

Combining the Integrals:
Substituting the integrals back into the original equation, we get:
$\frac{1}{2}\ln|y-1| - \frac{1}{2}\ln|y+1| = \frac{x^2}{2} + C_1$

Simplifying the equation, we get:
$\ln\left|\frac{y-1}{y+1}\right| = x^2 + C_1$

Applying Initial Condition:
Now, we can apply the initial condition $y(0) = 1$.

Plugging in the values, we get:
$\ln\left|\frac{1-1}{1+1}\right| = 0^2 + C_1$

Simplifying, we get:
$\ln\left|\frac{0}{2}\right| = C_1$

Which further simplifies to:
$\ln(0) = C_1$

The natural logarithm of 0 is undefined. Therefore, $C_1$ is undefined.

Solving for y:
Now, we can solve the equation for y.

Taking the exponent of both sides, we get:
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Community Answer
Ifdy/dx = x - y2 and y(0) = 1, then y(0.1) correct upto two decimal pl...
Concept:
Euler's Method to generate a numerical solution to an initial value problem of the form:
y' = f (x, y), y(x0) = y0
yn + 1 = yn + h f(xn, yn)
Calculation:
We have,
x0 =  0, y0 = 1, h = 0.1
x1 = x0 + h
For n = 0
⇒ y1 = y0 + hf(xn, yn)
⇒ y1 = 1 - 0.1 ×  (0 - 1)2
⇒ y1 = 1 - 0.1
⇒ y1 = 0. 9
For n = 1
⇒ y2 = y1 + hf(x1 - y12)
⇒ y2 = 0.9 + 0.1[0.1 - (0.9)2]
⇒ y2 = 0.9 + 0.1[0.1 - 0. 81]
⇒ y2 = 0.9 - 0.1 ×  0.71
⇒ y2 = 0.9 - 0.071
⇒ y2 = 0. 829
⇒ y2 = 0.83
∴ The approximately. two decimal place value is 0.83 
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Ifdy/dx = x - y2 and y(0) = 1, then y(0.1) correct upto two decimal places (approx.) is:a)0.85b)0.84c)0.91d)1.01Correct answer is option 'B'. Can you explain this answer?
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