To find the equation of a line that is perpendicular to the given line xy = 7 and passes through the point (1, 1), we can follow these steps:
- Determine the slope of the given line: First, we need to rewrite the equation xy = 7 in a more familiar slope-intercept form (y = mx + b). We can express y in terms of x:
- Finding the slope: To find the slope at any point along this curve, we can differentiate y with respect to x. Using implicit differentiation, we get:
- Calculate the slope at the point (1, 1): Substituting x = 1 and y = 1 into the slope formula:
- Finding the slope of the perpendicular line: The slope of a line that is perpendicular to another line is the negative reciprocal of the original slope. Thus:
- Using the point-slope form of the line: Now that we have the slope of the perpendicular line and a point through which it passes, we can use the point-slope form of the equation of a line y – y1 = m(x – x1):
- Simplifying the equation: Distributing and simplifying this results in:
y = 7/x
d/dx(xy) = 0
From the product rule, we have y + x(dy/dx) = 0 which gives us dy/dx = -y/x.
m = -1/1 = -1.
Perpendicular slope = 1 (since the negative reciprocal of -1 is 1).
y – 1 = 1(x – 1)
y – 1 = x – 1
y = x.
In conclusion, the equation of the line that is perpendicular to xy = 7 and passes through the point (1, 1) is:
y = x