Answer:

Step-by-step explanation:
From the given information:
The diagrammatic interpretation of what the question is all about can be seen in the diagram attached below.
Now, let V(x) be the time needed for the runner to reach the buoy;
∴ We can say that,

In order to estimate the point along the shore, x meters from B, the runner should stop running and start swimming if he want to reach the buoy in the least time possible, then we need to differentiate the function of V(x) and relate it to zero.
i.e
The differential of V(x) = V'(x) =0
=





squaring both sides; we get


By cross multiplying; we get










Answer:
=========
<h2>Given</h2>
<h3>Line 1</h3>
<h3>Line 2</h3>
- Passing through the points (4, 3) and (5, - 3)
<h2>To find</h2>
- The value of k, if the lines are perpendicular
<h2>Solution</h2>
We know the perpendicular lines have opposite reciprocal slopes, that is the product of their slopes is - 1.
Find the slope of line 1 by converting the equation into slope-intercept from standard form:
<u><em>Info:</em></u>
- <em>standard form is ⇒ ax + by + c = 0, </em>
- <em>slope - intercept form is ⇒ y = mx + b, where m is the slope</em>
- 3x - ky + 7 = 0
- ky = 3x + 7
- y = (3/k)x + 7/k
Its slope is 3/k.
Find the slope of line 2, using the slope formula:
- m = (y₂ - y₁)/(x₂ - x₁) = (-3 - 3)/(5 - 4) = - 6/1 = - 6
We have both the slopes now. Find their product:
- (3/k)*(- 6) = - 1
- - 18/k = - 1
- k = 18
So when k is 18, the lines are perpendicular.
Multiply the numerator and denominator by 7×2 = 14 to eliminate the denominators of those fractions:

Rationalize the denominator by multiplying both numerator and denominator by √10:

Lastly, cancel the common factor of 2 in both the numerator and denominator (which comes from 6 = 2×3 and 490 = 2×245):
