Find the extreme values of the function and where they occur? 1/x^2+1 i solve it as 0.5 is minimum at x= -1 but it is false!

1 Answer
Jun 25, 2018

f[x] = 1f[x]=1 when x=0x=0

Explanation:

f[x]f[x]=1/[x^2+1]1x2+1......Differentiating using the quotient rule.

d/dx[u/v]ddx[uv]= [[vdu]/[dx]-[udv]/[dx]]/[v^2]vdudxudvdxv2 = [[x^2+1][0] - [2x]]/[x^2+1]^2[x2+1][0][2x][x2+1]2 = - [2x]/[x^2+1]^22x[x2+1]2[ where uu and vv are both functions of xx, in this case v= x^2+1v=x2+1 and u = 1u=1]

Therefore - [2x]/[x^2+1]^22x[x2+1]2 = 00 for max/min. i.e, x=0x=0

When x=0x=0, f[x]f[x] = 1/[ 0^2+1]^21[02+1]2 = 11.