# Find the particular solution of the differential equation $$\frac{dy}{dx}$$+2x=5 given that y=5, when x=1.

Category: QuestionsFind the particular solution of the differential equation $$\frac{dy}{dx}$$+2x=5 given that y=5, when x=1.
Editor">Editor Staff asked 11 months ago

Find the particular solution of the differential equation $$\frac{dy}{dx}$$+2x=5 given that y=5, when x=1.

(a) y=5x+x^2+1

(b) y=x-x^2+4

(c) y=5x-x^2+1

(d) y=5x-x^2

I have been asked this question by my school principal while I was bunking the class.

Question is from Methods of Solving First Order & First Degree Differential Equations in chapter Differential Equations of Mathematics – Class 12
NCERT Solutions for Subject Clas 12 Math Select the correct answer from above options
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Editor">Editor Staff answered 11 months ago

Correct choice is (c) y=5x-x^2+1

Best explanation: Given that, $$\frac{dy}{dx}+2x=5$$

$$\frac{dy}{dx}=5-2x$$

Separating the variables, we get

dy=(5-2x)dx

Integrating both sides, we get

$$\int dy=\int 5-2x \,dx$$

y=5x-x^2+C –(1)

Given that, y=5, when x=1

⇒5=5(1)-(1)^2+C

∴C=1

Substituting value of C to equation (1), we get

y=5x-x^2+1 which is the particular solution of the given differential equation.