Skip to main contentSkip to solution

If f(x)=∫x+8x−8 dx;f(8)=24log⁡e2f(x)=\int \sqrt{\dfrac{x+8}{x-8}}\,dx; f(8)=24\log_e 2, then f(10)f(10) is equal to:

Solution

✅ Correct Option: 1

Rationalise: x+8x−8=x+8x2−64\sqrt{\dfrac{x+8}{x-8}} = \dfrac{x+8}{\sqrt{x^2-64}}.

So f(x)=x2−64+8log⁡e∣x+x2−64∣+Cf(x) = \sqrt{x^2-64} + 8\log_e|x+\sqrt{x^2-64}| + C.

At x=8x=8: 0+8log⁡e8=24log⁡e20 + 8\log_e 8 = 24\log_e 2, so C=0C=0.

Then f(10)=6+8log⁡e16=6+32log⁡e2f(10) = 6 + 8\log_e 16 = 6 + 32\log_e 2.

Keyboard Shortcuts

  • Left arrow: Previous question
  • Right arrow: Next question
  • S key: Jump to solution
  • Q key: Jump to question