Question

The equation of tangent to curve $y=e^{-x}$ at the points where the curve cuts the line x = 1 is

• A. x+ y = e
• B. e (x + y) = 1
• C. y + ex = 1
• D. None of these

Answer 1

The correct option is D None of these

$y=e^{-x}(x=1)(y=\frac{1}{e})\frac{dy}{dx}=-e^{-x}=-\frac{1}{e}(y-\frac{1}{e})=\frac{-(x-1)}{e}ey+x=2$