Advertisements
Advertisements
Question
`intcos^3x dx` = ______
Options
`1/4 sinx + 1/12 sin3x + c`
`3/4sinx + 1/3sin 3x + c`
`3/4sinx + 1/12 sin3x + c`
`1/3sinx + 1/6sin3x + c`
MCQ
Fill in the Blanks
Advertisements
Solution
`intcos^3x dx` = `underline(3/4sinx + 1/12 sin3x + c)`
Explanation:
`intcos^3x dx`
= `int(3cosx + cos3x)/4 dx` .....[∵ cos 3x = 4cos3x - 3cosx]
= `3/4intcosx dx + 1/4intcos3x dx`
= `3/4sinx + 1/4((sin3x)/3) + c`
= `(3sinx)/4 + (sin3x)/12 + c`
= `3/4sinx + 1/12sin3x + c`
shaalaa.com
Is there an error in this question or solution?
