Skip to main contentSkip to solution

The area bounded by 2x+y=8,y=a2x+y=8, y=a and y=a+2y=a+2 with y-axis is 5 sq.units where a>0a>0, then the value of aa is:

Solution

✅ Correct Option: 2

From the line, x=8−y2x = \dfrac{8-y}{2}, so the area is ∫aa+28−y2 dy\int_a^{a+2}\dfrac{8-y}{2}\,dy.

Evaluating gives 12[16−(a+2)2−a22]=12[16−2a−2]=7−a\dfrac{1}{2}\left[16 - \dfrac{(a+2)^2-a^2}{2}\right] = \dfrac{1}{2}[16-2a-2] = 7-a.

Setting 7−a=57-a=5 gives a=2a=2.

Keyboard Shortcuts

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