JEE Main & Advanced Mathematics Differentiation Question Bank Differentiation by Substitution

  • question_answer
    If \[x=A\cos 4t+B\sin 4t\],then \[\frac{{{d}^{2}}x}{d{{t}^{2}}}=\] [Karnataka CET 2004]

    A)            ? 16x

    B)            16 x

    C)            x

    D)            ? x

    Correct Answer: A

    Solution :

               \[x=A\cos 4t+B\sin 4t\]                    Differentiate w.r.t. t, \[\frac{dx}{dt}=-4A\sin 4t+4B\cos 4t\]                    Again, differentiate w.r.t. t, \[\frac{{{d}^{2}}x}{d{{t}^{2}}}=-16A\cos 4t-16B\sin 4t\]                    \[\frac{{{d}^{2}}x}{d{{t}^{2}}}=-16[A\cos 4t+B\sin 4t]\]. Hence, \[\frac{{{d}^{2}}x}{d{{t}^{2}}}=-16x\].


You need to login to perform this action.
You will be redirected in 3 sec spinner