Find the po

We have, f(x) = sin x – cos x

Differentiate w.r.t x, we get,

f ‘(x) = cos x + sin x

For, the point of local maxima and minima,

f ’(x) = 0

= cos x = – sin x => tan x = – 1 = x =

Again differentiate w.r.t x

f ’’(x) = – sin x + cos x

f ”= – sin + cos = –

f ”= – sin + cos = –

Therefore, by second derivative test, x = is a point of local maxima and the local maximum of f at x = is

F” = sin – cos =

F” = sin – cos =