Question

show that the inflection points for y=sinx/x lie on the curve y^2(x^4 +4)=4

Answer 1

find the second derivative wrt x of
\[ y = \frac{\sin x }{x} \]
and set y'' = 0
you will get an expression with sin x and cos x in it.

from \( y = \frac{\sin x }{x}, \sin x = x y \)
also, \( \cos x = \sqrt{1 - x^2 y^2}\)
sub in those values.
you will need to do a bit of algebra but you can (eventually) get
y^2(x^4 +4)=4

Answer 2

post how far you get.