Question

The length of normal to the curve x = $a(\theta +sin\theta )$ at the point $\theta =\pi /2$ is
[RPET 1999]

• A. 2a
• B. a/2
• C. $\sqrt{2}a$
• D. $a/\sqrt{2}$

Answer 1

The correct option is A 2a

Let y = $x^{n+1};$ then $y_1=(n+1)x^n$
$y_2=n(n+1)x^{n-1}$
$y_3=n(n+1)(n-1)x^{n-2}$
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$y_n=(n+1)!x.$