Question Number 85865 by subhankar10 last updated on 25/Mar/20 $$\mathrm{prove}\:\mathrm{that}\: \\ $$$$\mathrm{curl}\left(\mathrm{r}^{\mathrm{n}} \overset{\rightarrow} {\mathrm{c}}×\overset{\rightarrow} {\mathrm{r}}\right)=\left(\mathrm{n}+\mathrm{2}\right)\mathrm{r}^{\mathrm{n}} \overset{\rightarrow} {\mathrm{c}}−\mathrm{nr}^{\mathrm{n}−\mathrm{2}} \left(\overset{\rightarrow} {\mathrm{r}}.\overset{\rightarrow} {\mathrm{c}}\right)\:\:. \\ $$$$\mathrm{where}\:\mathrm{c}\:\mathrm{is}\:\mathrm{the}\:\mathrm{constant}\:\mathrm{vector}. \\ $$ Answered…
Question Number 20194 by ajfour last updated on 23/Aug/17 $${A}\:{plane}\:{is}\:{drawn}\:{through}\:{the}\: \\ $$$${midpoint}\:{of}\:{a}\:{diagonal}\:{of}\:{a}\:{cube} \\ $$$${perpendicular}\:{to}\:{the}\:{diagonal}. \\ $$$${Determine}\:{the}\:{area}\:{of}\:{the}\:{figure} \\ $$$${resulting}\:{from}\:{the}\:{section}\:{of}\:{the} \\ $$$${cube}\:{cut}\:{by}\:{this}\:{plane}\:{if}\:{the}\:{edge} \\ $$$${of}\:{the}\:{cube}\:{is}\:{equal}\:{to}\:\boldsymbol{{a}}. \\ $$ Commented…
Question Number 19976 by Tinkutara last updated on 19/Aug/17 $$\mathrm{Three}\:\mathrm{vectors}\:\overset{\rightarrow} {{A}},\:\overset{\rightarrow} {{B}}\:\mathrm{and}\:\overset{\rightarrow} {{C}}\:\mathrm{add}\:\mathrm{up}\:\mathrm{to} \\ $$$$\mathrm{zero}.\:\mathrm{Find}\:\mathrm{which}\:\mathrm{is}\:\mathrm{false}. \\ $$$$\left({a}\right)\:\left(\overset{\rightarrow} {{A}}×\overset{\rightarrow} {{B}}\right)×\overset{\rightarrow} {{C}}\:\mathrm{is}\:\mathrm{not}\:\mathrm{zero}\:\mathrm{unless}\:\overset{\rightarrow} {{B}},\:\overset{\rightarrow} {{C}} \\ $$$$\mathrm{are}\:\mathrm{parallel} \\…
Question Number 19857 by Nayon last updated on 16/Aug/17 $${proof}\:{that}\:\left(\underset{−} {{a}}+\underset{−} {{b}}\right).\underset{−} {{c}}=\underset{−} {{a}}.\underset{−} {{c}}+\underset{−} {{b}}.\underset{−} {{c}} \\ $$$${or}\:{the}\:{distribiuting}\:{law}\:{of}\:{dot}\:{products} \\ $$$$ \\ $$ Commented by…
Question Number 19554 by Nayon last updated on 12/Aug/17 $${proof}\:\left(\overset{−} {{a}}+\overset{−} {{b}}\right).\overset{−} {{c}}=\overset{−} {{a}}.\overset{−} {{c}}+\overset{−} {{b}}.\overset{−} {{c}} \\ $$ Terms of Service Privacy Policy Contact:…
Question Number 84849 by M±th+et£s last updated on 16/Mar/20 $${ABC}\:{is}\:{a}\:{triangle}\: \\ $$$${prove}\:{that} \\ $$$${sinA}+{sinB}+{sinC}>{sinA}\:{sinB}\:{sinC} \\ $$ Commented by ajfour last updated on 16/Mar/20 $$\mathrm{0}<\:\mathrm{sin}\:{A}\:,\:\mathrm{sin}\:{B},\:\mathrm{sin}\:{C}\:\leqslant\:\mathrm{1} \\…
Question Number 84641 by M±th+et£s last updated on 14/Mar/20 Commented by M±th+et£s last updated on 14/Mar/20 $${a}\:{square},\:{a}\:{circle}\:{and}\:{tow}\:{semicircles} \\ $$$${the}\:{are}\:{of}\:{the}\:{square}\:{is}\:\mathrm{4}.{what}\:{is}\:{the} \\ $$$${length}\:{of}\:{the}\:{blue}\:{lenght} \\ $$ Answered by…
Question Number 18909 by Nayon last updated on 01/Aug/17 $${What}\:{does}\:\underset{} {{a}}.\underset{} {{b}}\:\:{and}\:\underset{} {{a}}×\underset{} {{b}}\:{means}\:? \\ $$$${someone}\:{please}\:{explain}\:{it}. \\ $$ Commented by mrW1 last updated on 02/Aug/17…
Question Number 18907 by Nayon last updated on 01/Aug/17 $${Why}\:{Does}\: \\ $$$$\overset{\rightarrow} {{A}}.\overset{\rightarrow} {{B}}={ABCos}\theta?\: \\ $$ Commented by Nayon last updated on 01/Aug/17 $${Mr}.{w}\mathrm{1}\:{pls}\:{explain} \\…
Question Number 18908 by Nayon last updated on 01/Aug/17 $${Why}\:{Does} \\ $$$$\mid\overset{\rightarrow} {{A}}×\overset{\rightarrow} {{B}}\mid={ABSin}\theta\:? \\ $$ Commented by mrW1 last updated on 02/Aug/17 $$\mathrm{You}\:\mathrm{can}\:\mathrm{not}\:\mathrm{ask}\:\mathrm{why}\:\mathrm{to}\:\mathrm{a}\:\mathrm{definition}. \\…