An exponential growth/decay word problem. If spraying of grasshoppers

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SUMMARY

The discussion focuses on solving a word problem related to exponential decay in the context of insecticide application for grasshopper control. The problem states that 800 kg/km² of insecticide kills 40% of the grasshoppers, and the goal is to determine the amount needed to kill 98%. The relevant equations include the exponential decay formula and the relationship between the amount of insecticide and the percentage of grasshoppers killed. Participants are working through the mathematical setup but express uncertainty about the next steps in the solution process.

PREREQUISITES
  • Understanding of exponential decay equations
  • Familiarity with integration techniques in calculus
  • Knowledge of logarithmic functions and their properties
  • Basic concepts of population dynamics in ecology
NEXT STEPS
  • Study the derivation and application of the exponential decay formula
  • Learn about the integration of differential equations in population modeling
  • Explore the concept of carrying capacity in ecological systems
  • Investigate the effects of varying insecticide concentrations on pest populations
USEFUL FOR

Students in ecology or mathematics, particularly those tackling problems involving exponential growth and decay, as well as anyone interested in pest control strategies and their mathematical modeling.

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Homework Statement


If spraying of grasshoppers with 800kg/km^2 of a certain insecticide will kill 40% of these insects, how much insecticide is needed to kill 98% of the grasshoppers?
(assume exponential relationship)

Homework Equations


\intdP/dt=\intkp
lnP=kt+c
e^(kt+c)=P

The Attempt at a Solution


I set up an equation relating the amount of insecticide to how many die (exp decay -k)
800kg/km^2=Po(e^-k(.4))
im unsure as where to go from here...or if I am even on the right path
 
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insecticide is the input not the output.
So,

G_alive/G_intial = exp(-k.insecticide used)

when insecticide used = 0 then G_alive/G_initial = 1 .. (no G killed)
 

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