Maths · Determining areas of the regions bounded by simple curves in standard forms

The area bounded by the axis, the curve \) and the lines and is equal to \) for

The area bounded by the \( x- \) axis, the curve \( y=f(x) \) and the lines \( x=1 \) and \( x=b \) is equal to \( (\sqrt{b^{2}+1}-\sqrt{2}) \) for all \( \boldsymbol{b}>1, \) then \( \boldsymbol{f}(\boldsymbol{x}) \) is

  • A. \( \sqrt{x-1} \)
  • B. \( \sqrt{x+1} \)
  • C. \( \sqrt{x^{2}+1} \)
  • D. \( \frac{x}{\sqrt{x^{2}+1}} \)

Step-by-step solution

The area from x=1 to x=b is ∫₁ᵇ f(x) dx = √(b²+1) - √2. Differentiating both sides w.r.t. b gives f(b) = b/√(b²+1), so f(x) = x/√(x²+1).
Practise more in this unitView MCQsSign up for full question bank