H3 #2 a

Use the Bisection Method to find a solution of 9x^4+18x^3+38x^2-55x+14=0
our answer is x=0.366238

Step 1: populate the spreadsheet with our givens:

a0	b0	f(a0)	f(b0)
0	0.5	=9*A2^4 +18*A2^3 +38*A2^2 -55*A2 +14	=9*B2^4 +18*B2^3 +38*B2^2 -55*B2 +14

Step 2: use the bisection method to find c0 (the midpoint of a0 and b0) and f(c0)

c0	f(c0)
=(A2+B2)/2	=9*E2^4+18*E2^3+38*E2^2-55*E2+14

Step 3: From here you check to see if the sign of f(a0) matches f(c0), if it does, change a0 to c0. Do the same checking f(b0) against f(c0)

=IF(SIGN(C2)=SIGN(F2); E2;A2)

=IF(SIGN(D2)=SIGN(F2); E2;B2)

if all is done correctly, you should be able to drag the columns down an by the 20th iteration the numbers should match up.