Let A be a matrix. Show that the matrix AAt is symmetric. |Hint: Show that this matrix equals its transpose w ith the help of Exercise 17b.]

Tnt.o l*^ a-or(AJry,totra- i I,l Sgs*qr\ns LinflBxEgdryffis * t!^ro* e{*aJneyt€in q Va,r"alotesX, Yr," X,^ iq.\un €l usiid o{ +-ln.f-rrn Of *hl. {otrcwing.; I , ,X,QrXzt-*"*@nYn=b iwh onf,F" ,: a.cnnefa,n* o-,fid{ is cLva,\ri\2, . Cvo.anw.n["qJG) ^ '{"; i [Ovcu.'fl--p] "Vafia]o\ps At-u;A\q ecprateA ,{X4;rnptto+ ^ ug*lsyts:o^dd^h\onieu-bhrac*ion O f,=l' {inla,,vq @ Y+ g:r1 "varn^a.,bllsoarr".-b,-\ddific^a e *x ; r Srl,"*^;d,+ vanahks g) X,-ZYr-1=X3:g*T$'ffitr-uLao su$ec.rrptta rqVsat* (sin9)y,- tt ,\iq-firt".Ji"-V';;{tZi-r,o-" @j Yr=* rtetLs, q- so is iltnmp\ts o+ run lin