Differentiate ${{x}^{\sin x}},x>0$ with respect to $x$ .
Answer
665.7k+ views
Hint: Start by using $y={{x}^{\sin x}}$ and taking log of both the sides of the equation. Now use the identity that $\log {{a}^{b}}=b\log a$ and differentiate both sides of the equation with respect to x. Use the uv rule of differentiation, i.e., $\dfrac{d\left( uv \right)}{dx}=v\dfrac{du}{dx}+u\dfrac{dv}{dx}$ .
Complete step-by-step solution -
Let us start the solution to the above question by letting ${{x}^{\sin x}},x>0$ to be equal to y. So, we can say
$y={{x}^{\sin x}}............(i)$
Now we know, if we take log of both sides of the equation, we know that the equation remains valid. So, we will take log of both sides of the equation. On doing so, we get
$\log y=\log {{x}^{\sin x}}$
Now, we know that $\log {{a}^{b}}=b\log a$ . So, using this identity in our equation, we get
$\log y=\sin x\log x$
Now we will differentiate both sides of the equation with respect to x. On doing so, we get
$\dfrac{d\left( \log y \right)}{dx}=\dfrac{d\left( \sin x\log x \right)}{dx}$
Using the uv rule of differentiation, i.e., $\dfrac{d\left( uv \right)}{dx}=v\dfrac{du}{dx}+u\dfrac{dv}{dx}$ and $\dfrac{d\left( \log y \right)}{dx}=\dfrac{1}{y}\dfrac{dy}{dx}$ , we get
$\dfrac{1}{y}\dfrac{dy}{dx}=\dfrac{\log xd\left( \sin x \right)}{dx}+\dfrac{\sin xd\left( \log x \right)}{dx}$
Now, we know that the derivative of $\sin x\text{ is cosx}$ and $\log x\text{ is }\dfrac{1}{x}$ . So, using this in our equation, we get
$\dfrac{1}{y}\dfrac{dy}{dx}=\log x\times \operatorname{cosx}+\sin x\times \dfrac{1}{x}$
$\Rightarrow \dfrac{dy}{dx}=y\left( \log x\times \operatorname{cosx}+\sin x\times \dfrac{1}{x} \right)$
Now, we will put the value of y from equation (i). On doing so, we get
$\dfrac{dy}{dx}={{x}^{\sin x}}\left( cosx\log x+\dfrac{\sin x}{x} \right)$
Therefore, we can conclude that the derivative of ${{x}^{\sin x}},x>0$ is ${{x}^{\sin x}}\left( cosx\log x+\dfrac{\sin x}{x} \right).$
Note: Be careful with the signs and calculations as in such questions, the possibility of making a mistake is either of the sign or a calculation error. Also, remember that for taking log of both the sides of the equation, both the sides must be positive. In the above question the RHS is positive as it is given that x>0, if it was not mentioned, we could not have taken log of both the sides and solved the equation.
Complete step-by-step solution -
Let us start the solution to the above question by letting ${{x}^{\sin x}},x>0$ to be equal to y. So, we can say
$y={{x}^{\sin x}}............(i)$
Now we know, if we take log of both sides of the equation, we know that the equation remains valid. So, we will take log of both sides of the equation. On doing so, we get
$\log y=\log {{x}^{\sin x}}$
Now, we know that $\log {{a}^{b}}=b\log a$ . So, using this identity in our equation, we get
$\log y=\sin x\log x$
Now we will differentiate both sides of the equation with respect to x. On doing so, we get
$\dfrac{d\left( \log y \right)}{dx}=\dfrac{d\left( \sin x\log x \right)}{dx}$
Using the uv rule of differentiation, i.e., $\dfrac{d\left( uv \right)}{dx}=v\dfrac{du}{dx}+u\dfrac{dv}{dx}$ and $\dfrac{d\left( \log y \right)}{dx}=\dfrac{1}{y}\dfrac{dy}{dx}$ , we get
$\dfrac{1}{y}\dfrac{dy}{dx}=\dfrac{\log xd\left( \sin x \right)}{dx}+\dfrac{\sin xd\left( \log x \right)}{dx}$
Now, we know that the derivative of $\sin x\text{ is cosx}$ and $\log x\text{ is }\dfrac{1}{x}$ . So, using this in our equation, we get
$\dfrac{1}{y}\dfrac{dy}{dx}=\log x\times \operatorname{cosx}+\sin x\times \dfrac{1}{x}$
$\Rightarrow \dfrac{dy}{dx}=y\left( \log x\times \operatorname{cosx}+\sin x\times \dfrac{1}{x} \right)$
Now, we will put the value of y from equation (i). On doing so, we get
$\dfrac{dy}{dx}={{x}^{\sin x}}\left( cosx\log x+\dfrac{\sin x}{x} \right)$
Therefore, we can conclude that the derivative of ${{x}^{\sin x}},x>0$ is ${{x}^{\sin x}}\left( cosx\log x+\dfrac{\sin x}{x} \right).$
Note: Be careful with the signs and calculations as in such questions, the possibility of making a mistake is either of the sign or a calculation error. Also, remember that for taking log of both the sides of the equation, both the sides must be positive. In the above question the RHS is positive as it is given that x>0, if it was not mentioned, we could not have taken log of both the sides and solved the equation.
Recently Updated Pages
If x a + bt + ct2 where x is in meters and t is in class 11 physics CBSE

A car covers the first half distance between two places class 11 physics CBSE

The resultant of two vectors overrightarrow P and overrightarrow class 11 physics CBSE

Find the value of cos 135 class 11 maths CBSE

A mass M is held in place by an applied force F and class 11 physics CBSE

A solution of glucose in water is labelled as 10 dfracwv class 11 chemistry CBSE

Trending doubts
One Metric ton is equal to kg A 10000 B 1000 C 100 class 11 physics CBSE

Find the value of the expression given below sin 30circ class 11 maths CBSE

What do you mean by retardation What is its SI uni class 11 physics CBSE

Draw a diagram of nephron and explain its structur class 11 biology CBSE

10 examples of friction in our daily life

Difference between physical and chemical change class 11 chemistry CBSE

