Q48 / 90 · JEE Main 2024 (01 Feb Shift 2) · Mathematics

If y=x+1x2−xxx+x+x+1153cos2x−5cos3x, then 96y'π6 is equal to:

Correct answer: 105

Solution

Given:y=x+1x2-xxx+x+x+1153cos5x-5cos3x

⇒y=x+1x2-xx-1xx+x+xx-1+1153cos5x-5cos3x

⇒y=x+1x2-xx-1xx+x+1x-1+1153cos5x-5cos3x

⇒y=x+1x2-xx-1xx3-1+1153cos5x-5cos3x

⇒y=x+1xx3-1x-1xx3-1+1153cos5x-5cos3x

⇒y=x+1x-1+1153cos5x-5cos3x

⇒y=x-1+1153cos5x-5cos3x

⇒dydx=1+11515cos4x-sinx+15cos2xsinx

⇒dydx=1+cos4x-sinx+cos2xsinx

⇒y'π6=1+cos4π6-sinπ6+cos2π6sinπ6

⇒y'π6=1+3424-12+3222×12

⇒y'π6=1-932+38

⇒y'π6=32-9+1232

⇒y'π6=3532

⇒96y'π6=35×3

⇒96y'π6=105

Hence, the correct answer is 105.

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