The equation of the tangent at any point of the curve \( x = a \cos 2t, \quad y = 2\sqrt{2} \, a \sin t \), with m as its slope is
Step-by-step Solution:
CONCEPT:
If \( x = f(t) \), \( y = g(t) \), where \( t \) is a parameter, then
\[
\frac{dy}{dx} = \frac{g'(t)}{f'(t)}
\]
The slope of the tangent to a curve \( y = f(x) \) at any point is given by:
\[
m = \frac{dy}{dx}
\]
The equation of a tangent to a curve \( y = f(x) \) is given by:
\[
y - y_1 = m (x - x_1)
\]
CALCULATION:
The parametric equations of the curve are:
\[
x = a \cos 2t, \quad y = 2\sqrt{2} \, a \sin t
\]
Since the slope of the tangent to a curve \( y = f(x) \) at any point is given by \( m = \frac{dy}{dx} \), we calculate:
\[
m = \frac{dy}{dx} = \frac{-\sqrt{2}}{2 \times \sin t}
\]
Solving for \( \sin t \):
\[
\sin t = \frac{-\sqrt{2}}{2m}
\]
Using the given equations:
\[
x = a \cos 2t, \quad y = 2\sqrt{2} \, a \sin t
\]
Substituting \( \sin t \) in \( x \) and \( y \), we get:
\[
y = \frac{-2a}{m}, \quad x = a \left( 1 - \frac{1}{m^2} \right)
\]
Since the equation of a tangent to the curve \( y = f(x) \) is:
\[
y - y_1 = m (x - x_1)
\]
We use the point \( \left( a \left( 1 - \frac{1}{m^2} \right), \frac{-2a}{m} \right) \) to get:
\[
y + \frac{2a}{m} = m \left[ x - a \left( 1 - \frac{1}{m^2} \right) \right]
\]
Simplifying further, we obtain:
\[
y = mx - a \left( m + \frac{1}{m} \right)
\]
Thus, option B is the correct answer.