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Need solution for RD Sharma Maths Class 12 Chapter 18 Indefinite Integrals Excercise Very Short answers Question 46

Answers (1)

Answer:\frac{2^{x}}{\ln 2}+c

Hint: You must know about the integral rule of logarithmic functions.

Given:\int {2^{x}}dx

Solution:

\begin{aligned} &\int 2^{x} d x \\ &e^{\ln 2}=2 \\ &\int 2^{x} d x=\int\left(e^{\ln 2}\right)^{x} \\ &=\int e^{\ln 2} d x \\ &\text { Let } u=x \ln 2, \\ &\frac{d u}{d x}=\ln 2, \\ &d x=\frac{d u}{\ln 2} \\ &\int e^{x \ln 2} d x=\int e^{u} \cdot \frac{d u}{\ln 2} \end{aligned}

\begin{aligned} &=\frac{1}{\ln 2} \int e^{u} d u \\ &=\frac{1}{\ln 2} e^{u}+c \\ &=\frac{1}{\ln 2} e^{x \ln 2}+c \\ &=\frac{1}{\ln 2}\left(e^{\ln 2}\right)^{x}+c \quad\quad\quad\quad\quad\therefore e^{\ln 2}=2\\ &=\frac{1}{\ln 2} 2^{x}+c \end{aligned}

=\frac{2^{x}}{\ln 2}+c

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