What is \(\int\frac{(\cos x)^{1.5}−(\sin x)^{1.5}}{\sqrt{\sin x⋅\cos x}}\)dx equal to ?

This question was previously asked in
NDA 02/2022 Mathematics Official Paper (Held On 04 Sep 2022)
View all NDA Papers >
  1. \(​\sqrt{\sin \text{x}}−\sqrt{\cos \text{x}}\) + c
  2. \(​\sqrt{\sin \text{x}}+\sqrt{\cos \text{x}}\) + c
  3. \(2\sqrt{\sin \text{x}}+2 \sqrt{\cos \text{x}}\) + c
  4. \(​\frac{1}{2}\sqrt{\sin \text{x}}+\frac{1}{2} \sqrt{\cos \text{x}}\) + c

Answer (Detailed Solution Below)

Option 3 : \(2\sqrt{\sin \text{x}}+2 \sqrt{\cos \text{x}}\) + c
Free
BSF HC RO/RM All India Mega Live Test
5.4 K Users
100 Questions 200 Marks 120 Mins

Detailed Solution

Download Solution PDF

Given,

I = \(\int\frac{(\cos x)^{1.5}−(\sin x)^{1.5}}{\sqrt{\sin x⋅\cos x}}dx\)

⇒ I = \(\int\frac{\cos x}{\sqrt{\sin x}}- \frac{\sin x}{\sqrt{\cos x}}dx\)

⇒ I = \(\int\frac{\cos x}{\sqrt{\sin x}}dx- \int \frac{\sin x}{\sqrt{\cos x}}dx\) = I1 - I2 (let)

Computing I1,

I1 = \(\int\frac{\cos x}{\sqrt{\sin x}}dx\)

Put sin x = t → cos x dx = dt

⇒ I1\(\int\frac{dt}{\sqrt{t}} = {t^{-{1 \over 2}+1} \over{-{1 \over 2}+1}} + c_1\)

⇒ I1 = \(2\sqrt t + c_1\)

⇒ I1 = \(2\sqrt {\sin x} + c_1\)

Similarly, 

I2 = \(\int\frac{\sin x}{\sqrt{\cos x}}dx\)

Put cos x = t → - sin x dx = dt

⇒ I2 = \(\int\frac{dt}{\sqrt{t}} = -{t^{-{1 \over 2}+1} \over{-{1 \over 2}+1}} + c_2\) 

⇒ I2 = \(-2\sqrt t + c_2\) 

⇒ I2 = \(-2\sqrt {\cos x} + c_2\) 

Putting these value in I,

⇒ I = I1 - I2 = \(2\sqrt {\sin x} + c_1\) - \((-2\sqrt {\cos x}) + c_2\)

⇒ I = \(2\sqrt{\sin \text{x}}+2 \sqrt{\cos \text{x}}\) + c

∴ The correct answer is option (3).

Latest NDA Updates

Last updated on May 30, 2025

->UPSC has released UPSC NDA 2 Notification on 28th May 2025 announcing the NDA 2 vacancies.

-> A total of 406 vacancies have been announced for NDA 2 Exam 2025.

->The NDA exam date 2025 has been announced for cycle 2. The written examination will be held on 14th September 2025.

-> Earlier, the UPSC NDA 1 Exam Result has been released on the official website.

-> The selection process for the NDA exam includes a Written Exam and SSB Interview.

-> Candidates who get successful selection under UPSC NDA will get a salary range between Rs. 15,600 to Rs. 39,100. 

-> Candidates must go through the NDA previous year question paper. Attempting the NDA mock test is also essential. 

More Calculus Questions

Get Free Access Now
Hot Links: teen patti master 51 bonus teen patti wealth teen patti master gold