Mathematics

Mathematics

Problem

Consider the differential equation dydx=2y\frac{dy}{dx}=2y and the function y=5e2xy=5e^{2x}. (a) Verify that y=5e2xy=5e^{2x} satisfies the differential equation for all real xx. Show all supporting work. (b) The general solution to the differential equation can be written in the form y=Ce2xy=Ce^{2x}. Determine the value of the constant CC that guarantees the particular solution passes through the point (0,5)(0,5), and justify your result. (c) Use your work from parts (a) and (b) to explain why no other function of the form y=Ce2xy=Ce^{2x} can pass through the point (0,5)(0,5) while still satisfying the differential equation.
Intuitive explanation

This problem tests whether you understand exponential growth and can verify a solution by substitution. The key insight is that exponential functions have a special property: their derivative is proportional to themselves. To check if y=5e2xy=5e^{2x} solves the equation, compute dydx\frac{dy}{dx} directly and see if it equals 2y2y—this is how you verify any proposed solution to a differential equation.

Intuitive explanation

This problem tests whether you understand exponential growth and can verify a solution by substitution. The key insight is that exponential functions have a special property: their derivative is proportional to themselves. To check if y=5e2xy=5e^{2x} solves the equation, compute dydx\frac{dy}{dx} directly and see if it equals 2y2y—this is how you verify any proposed solution to a differential equation.

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