Question

Differentiate

x cos
x
using first principle.​

Answer 1

Answer: d/dx{x cos x}=-x sin x+cosx

Step by step Explanation:

Given: Expression x cos x

To find: The derivative of given expression from first principle?

Solution: The derivative rule of first principle is

d/dx [a.b]=ax d/dx [b]+b x d/dx

Here,a=x and b=cos x

d/dx [x cos x]=x multiplied by d/dx [cos x] + cos x multiplied by d/dx

d/dx [x cos x]=x multiplied by [-sin x] + cos x multiplied by 1

d/dx [x cos x]=-x sin x +cos x

Therefore, deriative is d/dx [x cos x]=-x sin x+cos x

Answer 2

Step-by-step explanation:

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