"When should you use the agile method, and when should you use and engineering based method for developing a system?

"When should you use the agile method, and when should you use and engineering based method for developing a system? Support your answer. Make answer as brief as possible. "

Agile methods are adaptive in nature. There nature is to welcome and adapt changes. And alsothe agile processes focus on people rather than process so in a case where a system to bedeveloped is...