EduFarming
Your list · 0हिं

Type at least two letters. Press Esc to close.

↑↓ navigate↵ openTAB cycle filter

Homogeneous & Linear Differential Equations · Question 94 of 120

Question 94

EasyOriginal question

Every solution of dydx+4y=8\frac{dy}{dx} + 4y = 8 approaches the same value as x→∞x \to \infty. What is that value?

Options for question 94

Show the answer and explanation
CorrectNot quiteAnswer B

Correct answer: B

Explanation

  1. The factor e4xe^{4x} gives ye4x=2e4x+Cye^{4x} = 2e^{4x} + C, so y=2+Ce−4xy = 2 + Ce^{-4x}.

  2. As x→∞x \to \infty, Ce−4x→0Ce^{-4x} \to 0, so y→84=2y \to \frac{8}{4} = 2.

Worth noting

8 is QQ itself; the steady value is where 4y=84y = 8.

Concept
The long-run value of \(\frac{dy}{dx} + ay = b\)
Typical time
60 s
Your time
—
The rule this testsSolving linear equations
Practise this chapter →

Ten questions from Homogeneous & Linear Differential Equations, at your own pace.

Practise this chapter →

Ten questions from Homogeneous & Linear Differential Equations, at your own pace.