Deferensialkan y = x2 cos 2x

jawab

y = x².  cos 2x → y = u . v
u = x² → u' = 2x
v = cos 2x →v ' = - 2 sin 2x

y' = u'v + uv'
y' = (2x)(cos 2x) + (x²)(-2 sin 2x)
y' = 2x cos 2x - 2x² sin 2x

y = x² . cos 2x

Misal :
u = x² ---> u' = 2x
v = cos 2x ---> v' = -2 sin 2x

y = u . v
y' = u'v + uv'

••
y = x² . cos 2x
y' = 2x cos 2x - 2x² sin 2x ✓