a: \(\int\dfrac{1}{x^2}dx=\int x^{-2}dx=\dfrac{1}{-2+1}\cdot x^{-2+1}+C=-x^{-1}+C\)
b: \(\int\dfrac{1}{\sqrt{x}}dx=\int x^{\dfrac{1}{2}}dx=\dfrac{1}{\dfrac{1}{2}+1}\cdot x^{\dfrac{1}{2}+1}+C=\dfrac{2}{3}\cdot x^{\dfrac{3}{2}}+C\)
c: \(\int\dfrac{4}{x}dx=4\cdot ln\left|x\right|+C\)