Solving a Trigonometric Equation to Hit a Moving Target

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SUMMARY

The discussion centers on solving the trigonometric equation 40sinθcosθ - 10sinθ - 1 = 0 to determine the angle required to hit a moving target without using calculators. Participants suggest two methods: substituting cosθ with √(1 - sin²θ) or converting the equation to terms of tan(θ/2). These approaches facilitate manual calculations and provide a clear pathway to finding the solution.

PREREQUISITES
  • Understanding of trigonometric identities, specifically sin and cos functions.
  • Familiarity with the half-angle tangent identity, tan(θ/2).
  • Basic algebra skills for manipulating equations.
  • Knowledge of solving equations without calculators.
NEXT STEPS
  • Study trigonometric identities and their applications in solving equations.
  • Learn about the half-angle formulas and their derivations.
  • Practice solving trigonometric equations manually without calculators.
  • Explore real-world applications of trigonometry in physics, particularly in projectile motion.
USEFUL FOR

Students studying trigonometry, educators teaching mathematical concepts, and anyone interested in applying trigonometric principles to real-world problems such as physics and engineering.

peanut648
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So the orginial question asked what angle to fire a gun to hit a moving target, and i got all the way to 40sinθcosθ-10sinθ-1 = 0, but we aren't supposed to use calculators so how would you solve this by hand. Thanks!
 
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Hi peanut648! Welcome to PF! :smile:

Either use cosθ = √(1 - sin2θ), or write everything in terms of tan(θ/2). :wink:
 

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