ตอบ:
# "a) 856.022 $" #
# "b) 15.4 ปี" #
คำอธิบาย:
# "a)" exp (x) = e ^ x = 1 + x + x ^ 2/2 + x ^ 3/6 + … #
#t = 12, r = 0.045, P = 500 #
# => A = 500 * e ^ (0.045 * 12) = 500 * e ^ 0.54 #
#~~ 500*(1 + 0.54 + 0.54^2/2 + 0.54^3/6)#
#= 500*(1 + 0.54 + 0.1458 + 0.026244)#
#= 500*1.712044#
#= 856.022#
# "b)" A = 2P #
# => 2P = P * e ^ (0.045 * t) #
# => 2 = e ^ (0.045 * t) #
# => ln (2) = 0.045 * t #
# => t = ln (2) /0.045 = 15.4 "ปี" #