Differential Equations · Class 12 · CBSE · Science Mathematics

The general solution of dy/dx + y tan x = sin x, on an interval where cos x is non-zero, is:

Practice question from Differential Equations (Class 12 · CBSE · Science Mathematics), with the correct answer and a step-by-step solution.

hard · MCQ · Q-4A5852

The general solution of dy/dx + y tan x = sin x, on an interval where cos x is non-zero, is:

  1. A.y = C sec x + cos x
  2. B.y = cos x(C − ln|cos x|)Correct answer
  3. C.y = sin x(C + ln|sin x|)
  4. D.y = C cos x + sin x

Solution

The integrating factor is e∫tan⁡x dx=sec⁡xe^{\int \tan x\,dx}=\sec x. Thus, d(ysec⁡x)/dx=tan⁡xd(y\sec x)/dx=\tan x, giving ysec⁡x=−ln⁡∣cos⁡x∣+Cy\sec x=-\ln|\cos x|+C. Therefore, y=cos⁡x(C−ln⁡∣cos⁡x∣)y=\cos x(C-\ln|\cos x|).

More from Differential Equations

All of Differential Equations

Practise more Mathematics

Sign up free for adaptive practice on this chapter, with instant feedback and hints on every question.

Start practising free

Free to start · No credit card needed