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Question

Mathematics Question on Area of the region bounded

The area of the region bounded by the lines x73a+yb=4\frac{x}{7\sqrt{3a}} + \frac{y}{b} = 4, x=0x = 0, and y=0y = 0 is:

A

563ab\frac{56}{\sqrt{3ab}}

B

56a56a

C

ab2\frac{ab}{2}

D

3ab3ab

Answer

563ab\frac{56}{\sqrt{3ab}}

Explanation

Solution

The equation of the line is:

x73a+yb=4.\frac{x}{7\sqrt{3a}} + \frac{y}{b} = 4.

Rewriting:

bx+73ay=283ab.b \cdot x + 7\sqrt{3a} \cdot y = 28\sqrt{3ab}.

To find the intercepts:

1. When x=0x = 0, y=4by = 4b.
2. When y=0y = 0, x=283ax = 28\sqrt{3a}.

The lines x=0x = 0 and y=0y = 0, together with x73a+yb=4\frac{x}{7\sqrt{3a}} + \frac{y}{b} = 4, form a triangle with vertices:

(0,0),(283a,0),(0,4b).(0, 0), \quad (28\sqrt{3a}, 0), \quad (0, 4b).

The area of the triangle is:

Area=12×base×height,\text{Area} = \frac{1}{2} \times \text{base} \times \text{height},

where the base is 283a28\sqrt{3a} and the height is 4b4b:

Area=12×(283a)×(4b).\text{Area} = \frac{1}{2} \times (28\sqrt{3a}) \times (4b).

Simplify:

Area=12×1123ab=563ab.\text{Area} = \frac{1}{2} \times 112\sqrt{3ab} = 56\sqrt{3ab}.

Thus, the area of the region is:

563ab.56\sqrt{3ab}.