find the horizontal tangents of the curve and show work

y=5x^3-3x^5

1 answer

y'=15x^2-15x^4=0 (ie horizontal tangents have slope zero)
0=15x^2(1-x^2)=15x^2(1+x)(1-x)

x=0, x=+-1
find y for each of those

eg, when x=1, y=2, so equation is y=2