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Question: Answered & Verified by Expert
The value of limx0costanx-cosx4x4 is equal to
MathematicsLimitsJEE Main
Options:
  • A -13
  • B -112
  • C 12
  • D 1
Solution:
2028 Upvotes Verified Answer
The correct answer is: -112
costanx-cosx=2sinx+tanx2sinx-tanx2
limx0costanx-cosx4x4=limx02sinx+tanx2sinx-tantanx24x4
=limx02sinx+tanx2sinx-tanx24x4x+tanx2x-tanx2x2-tan2x4
=18limx0x2-tan2xx4
=18limx0x2-x+x33+215x5+....2x4
=18limx01x21-1+x23+215x4+....2=-112

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