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Q.
If equation of tangent to the curve $y=-e^{\frac{-x}{2}}$ where it crosses the $y$-axis is $\frac{x}{a}+\frac{y}{b}=1$, then $(a-b)$ is equal to
Application of Derivatives
Solution:
At $ x=0, y=-1$,
Also, $ y^{\prime}(0)=\frac{1}{2}$
$\therefore $ Equation of tangent is $( y +1)=\frac{1}{2}( x -0)$
$\Rightarrow \frac{x}{2}+\frac{y}{-1}=1 \Rightarrow(a-b)=2-(-1)=3$.