Mathematic Problems

y=8x2cos x

y=8gx

gx=x2cosx

gx=uvu=x2 ; v=cosx

g'=u'v-uv'v2

u'=2x ; v'=-sin x

g'=2x·cosx-x2·-sinxcos2x

g'=2x·cosx+x2·sin xcos2x

y=8gx

y'=8gxln 8 ·g'x

y'=8x2cos x·ln 8·2x·cosx+x2·sinxcos2x