The equation of the tangent to the curve $y=(2 x-1) e^{2(1-x)}$ at the point of its maximum, is
Answer & explanation
Correct answer: option 1
We have,
$y=(2 x-1) e^{2(1-x)}$
$\Rightarrow \frac{d y}{d x}=2 e^{2(1-x)}-2(2 x-1) e^{2(1-x)}$
$\Rightarrow \frac{d y}{d x}=2 e^{2(1-x)}(2-2 x)=4 e^{2(1-x)}(1-x)$
At points of maximum, we must have
$\frac{d y}{d x}=0 \Rightarrow x=1$
Now, $\frac{d^2 y}{d x^2}=-8 e^{2(1-x)}(1-x)-4 e^{2(1-x)}$
$\Rightarrow\left(\frac{d^2 y}{d x^2}\right)_{x=1}=-4<0$
So, y is maximum at x = 1. Clearly, y = 1 for x = 1.
Thus, the point of maximum is (1, 1). The equation of the tangent at (1, 1) is
$y-1=0(x-1) \Rightarrow y=1$