4
sin (x)*x
---------
4
/ 4 \ d |sin (x)*x| --|---------| dx\ 4 /
The derivative of a constant times a function is the constant times the derivative of the function.
Apply the product rule:
; to find :
Apply the power rule: goes to
; to find :
Let .
Apply the power rule: goes to
Then, apply the chain rule. Multiply by :
The derivative of sine is cosine:
The result of the chain rule is:
The result is:
So, the result is:
Now simplify:
The answer is:
4 sin (x) 3 ------- + x*sin (x)*cos(x) 4
2 / / 2 2 \ \ sin (x)*\- x*\sin (x) - 3*cos (x)/ + 2*cos(x)*sin(x)/
/ / 2 2 \ / 2 2 \ \ -\3*\sin (x) - 3*cos (x)/*sin(x) + 2*x*\- 3*cos (x) + 5*sin (x)/*cos(x)/*sin(x)