Consider a monic cubic polynomial f(x) with f(6)=7,f(−6)=2 and roots r,s,t Find the value of rs+st+rt.
f(x)=ax3+bx2+cx+da=1f(x)=x3+bx2+cx+d−b=r+s+tc=rs+rt+st−d=rst
So I am asked to find c
f(x)=x3+bx2+cx+df(6)=63+b∗62+c∗6+df(6)=216+36b+6c+d f(−6)=−216+36b−6c+d f(6)−f(−6)=432+12c=7−212c=−427c=35712
You need to check for careless errors.
