7 Given that \( y(1)=-3 \) and \( \frac{d y}{d x}=2 x+y \), what is the approximation for \( y(2) \) if Euler's method is used with a step size of 0.5 , starting at \( x=1 \) ?
Real Tutor Solution
Answer
Solution
Sign in to Unlock Answers for Free!
A Learning Platform Trusted by Millions of Real Students and Teachers.
Reviewed and approved by the UpStudy tutoring team
Extra Insights
To approximate \( y(2) \) using Euler's method with a step size of 0.5, we begin at \( x = 1 \) with \( y(1) = -3 \). 1. First, we calculate \( y(1.5) \) using the formula: \[ y(x + h) \approx y(x) + h \cdot f(x, y) \] where \( f(x, y) = \frac{d y}{d x} = 2x + y \). At \( x = 1 \): \[ f(1, -3) = 2(1) + (-3) = 2 - 3 = -1 \] Using \( h = 0.5 \): \[ y(1.5) \approx y(1) + 0.5 \cdot f(1, -3) = -3 + 0.5 \cdot (-1) = -3 - 0.5 = -3.5 \] 2. Next, we compute \( y(2) \): Now, at \( x = 1.5 \): \[ f(1.5, -3.5) = 2(1.5) + (-3.5) = 3 - 3.5 = -0.5 \] Using \( h = 0.5 \): \[ y(2) \approx y(1.5) + 0.5 \cdot f(1.5, -3.5) = -3.5 + 0.5 \cdot (-0.5) = -3.5 - 0.25 = -3.75 \] Thus, the approximation for \( y(2) \) using Euler's method is \( \boxed{-3.75} \).