x*cos(x)
d --(x*cos(x)) dx
Apply the product rule:
f(x)=xf{\left(x \right)} = xf(x)=x; to find ddxf(x)\frac{d}{d x} f{\left(x \right)}dxdf(x):
Apply the power rule: xxx goes to 111
g(x)=cos(x)g{\left(x \right)} = \cos{\left(x \right)}g(x)=cos(x); to find ddxg(x)\frac{d}{d x} g{\left(x \right)}dxdg(x):
The derivative of cosine is negative sine:
The result is: −xsin(x)+cos(x)- x \sin{\left(x \right)} + \cos{\left(x \right)}−xsin(x)+cos(x)
The answer is:
-x*sin(x) + cos(x)
-(2*sin(x) + x*cos(x))
-3*cos(x) + x*sin(x)