How do you differentiate f(x)=(e^x+sinx)(cot^2x+1) using the product rule?

1 Answer
Feb 24, 2018

(e^x+sinx)(-2cotxcsc^2x)+(cot^2x+1)(e^x+cosx)

is the function obtained after differentiating using the product rule for the function described by

f(x)=(e^x+sinx)(cot^2x+1)

Explanation:

Given:

f(x)=(e^x+sinx)(cot^2x+1)

Let

y=f(x)

u=(e^x+sinx)

v=(cot^2x+1)

By the product rule,

d/(dx)(uv)=u(dv)/(dx)+v(du)/(dx)

Here,

u=(e^x+sinx)

Differentiating wrt x

(du)/(dx)=d/(dx)(u)

d/(dx)(u)=d/(dx)(e^x+sinx)

By the sum rule

d/(dx)(e^x+sinx)=d/(dx)(e^x)+d/(dx)(sinx)

d/(dx)(e^x)=e^x

d/(dx)(esinx)=cosx

d/(dx)(e^x+sinx)=e^x+cosx

d/(dx)(u)=e^x+cosx

(du)/(dx)=e^x+cosx

v=(cot^2x+1)

Differentiating wrt x

(dv)/(dx)=d/(dx)(v)

d/(dx)(v)=d/(dx)(cot^2x+1)

By the sum rule

d/(dx)(cot^2x+1)=d/(dx)(cot^2x)+d/(dx)(1)

d/(dx)(cot^2x)=2cotx(-csc^2x)

d/(dx)(cot^2x)=-2cotxcsc^2x

d/(dx)(1)=0

d/(dx)(cot^2x+1)=-2cotxcsc^2x+0

d/(dx)(v)=-2cotxcsc^2x

(dv)/(dx)=-2cotxcsc^2x

d/(dx)(uv)=u(dv)/(dx)+v(du)/(dx)

u=(e^x+sinx)

v=(cot^2x+1)

(du)/(dx)=e^x+cosx

(dv)/(dx)=-2cotxcsc^2x

d/(dx)((e^x+sinx)(cot^2x+1))=(e^x+sinx)(-2cotxcsc^2x)+(cot^2x+1)(e^x+cosx)