Q55 / 150 · MHT CET 2016 · Mathematics

If Rolle's theorem for a function fx=exsin⁡x-cos⁡x is verified on π4,5π4 then the value of c is

  • A
    π3
  • B
    π2
  • C
    3π4
  • Correct answer
    D
    π

Solution

Given, fx=ex(sin⁡ x-cos⁡ x)
∴  f′x=excos⁡ x+sin⁡ x+sin⁡ x-cos⁡ xex
∴  f′x=2exsin⁡ x
To verify Rolle's Theorem.
f′c=0
2ecsin⁡ c=0
⇒ sin⁡ c=0
∴  c=π

Hence, the correct answer is option: 'D'.

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