\begin{gathered}a) \int{(x^4-8x^3+4x)}dx=\\ | \int{x^{\alpha}dx}= \frac{x^{\alpha+1}}{\alpha+1}+C|\\ = \int{x^4}dx-8\int{x^3}dx+4\int{x^1}dx=\\ = \frac{x^{4+1}}{4+1}-8 \frac{x^{3+1}}{3+1}+4 \frac{x^{1+1}}{1+1}+C=\\ = \frac{x^5}{5}- \frac{8x^4}{4}+ \frac{4x^2}{2}+C=\\ = \frac{x^5}{5}-2x^4+2x^2+c;\\ \end{gathered}a)∫(x4−8x3+4x)dx=∣∫xαdx=α+1xα+1+C∣=∫x4dx−8∫x3dx+4∫x1dx==4+1x4+1−83+1x3+1+41+1x1+1+C==5x5−48x4+24x2+C==5x5−2x4+2x2+c;
\begin{gathered}b) \int{\cos(2x)sin(x)}dx=|d(\cos(x))=-\sin(x)dx|=\\ =-\int{\cos(2x)d(\cos(x))}=\\ |\cos(2\alpha)=\cos^2\alpha-\sin^2\alpha=2\cos^2\alpha-1=1-2\sin^2\alpha|\\ =-\int{(2\cos^2(x)-1)}d(\cos(x))=| t=\cos(x)|=\\ =-\int{(2t^2-1)}dt=|\int{x^{alpha}}dx= \frac{x^{\alpha+1}}{\alpha+1}+C|\\ =-2\int{t^2}dt+\int{t^0}dt=-2 \frac{t^{2+1}}{2+1}+ \frac{t^{0+1}}{0+1}=\\ =- \frac{2}{3}t^3+t+C=|t=\cos(x)|=\cos(x)- \frac{2}{3}\cos^3(x)+C=\\ \cos(x)(1- \frac{2}{3}\cos^2(x))+C=\\ =\cos(x)(1- \frac{2}{3}(1-\sin^2(x))+C= \end{gathered}b)∫cos(2x)sin(x)dx=∣d(cos(x))=−sin(x)dx∣==−∫cos(2x)d(cos(x))=∣cos(2α)=cos2α−sin2α=2cos2α−1=1−2sin2α∣=−∫(2cos2(x)−1)d(cos(x))=∣t=cos(x)∣==−∫(2t2−1)dt=∣∫xalphadx=α+1xα+1+C∣=−2∫t2dt+∫t0dt=−22+1t2+1+0+1t0+1==−32t3+t+C=∣t=cos(x)∣=cos(x)−32cos3(x)+C=cos(x)(1−32cos2(x))+C==cos(x)(1−32(1−sin2(x))+C=
\begin{gathered}=\cos(x)(1- \frac{2}{3}+ \frac{2}{3}\sin^2(x))+C=\\ =\cos(x)( \frac{1}{3}+ \frac{2}{3}\sin^2(x))+C=\\ = \frac{1}{3}\cos(x)(1+2\sin^2(x))+C; \end{gathered}=cos(x)(1−32+32sin2(x))+C==cos(x)(31+32sin2(x))+C==31cos(x)(1+2sin2(x))+C;
\begin{gathered}c)\int(e^{3x}+1)dx=\int{e^{3x}}dx+\int{}dx=\\ |\int{e^x}dx=e^x+C; \int{x^\alpha}dx= \frac{x^{\alpha+1}}{\alpha+1}+C;d(x)= \frac{1}{3}dx|}\\ = \frac{1}{3}\int{e^{3x}}d(3x)+\int{x^0}dx=\\ = \frac{1}{3}e^{3x}+ \frac{x^{0+1}}{0+1}+C=\\ = \frac{1}{3}e^{3x}+x+C \end{gathered}
