Question Number 34528 by ajfour last updated on 07/May/18
$${Find}\:{radius}\:{c}\:{in}\:{terms}\:{of}\:{radii} \\ $$$${a}\:{and}\:{b}. \\ $$
Commented by ajfour last updated on 07/May/18
Answered by rahul 19 last updated on 07/May/18
$$\frac{\mathrm{1}}{\sqrt{{c}}}\:=\:\frac{\mathrm{1}}{\sqrt{{a}}}\:+\:\frac{\mathrm{1}}{\sqrt{{b}}}\:. \\ $$
Commented by ajfour last updated on 07/May/18
$${true},\:{but}\:{how}\:{do}\:{you}\:{arrive}\:{at}\:{it}\:? \\ $$
Commented by rahul 19 last updated on 07/May/18
check question no. 34543
Commented by ajfour last updated on 08/May/18
very nice.