The solution of dy/dx = −3y with y(0) = 6 is

Answer and explanation

Correct answer: A. y = 6e^(−3x)

  1. Step 1: This is separable: dy/y = −3 dx, so ln y = −3x + C. Step 2. With y(0) = 6 the solution is y = 6e^(−3x). Answer: y = 6e^(−3x). Why not the others: y = 6e^(3x) is what you get if you get the sign of the exponent wrong. y = 6 − 3x is what you get if you assume a linear solution. y = 6e^(−x/3) is what you get if you invert the coefficient.

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