Solving a Trigonometric Equation: v^2*sin(180-2theta2)/g

AI Thread Summary
To solve the trigonometric equation v^2*sin(180-2theta2)/g, the first step involves substituting theta1 with 90 - theta2. The next crucial step is to demonstrate the equality of both sides of the equation using trigonometric identities. Simplifying expressions like sin(180-x) and sin(90-x) is essential in this process. Utilizing the sum and difference identities will aid in the simplification. Understanding these identities is key to progressing in the solution.
DeltaForce
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Homework Statement
Show that the range of the projectile is the same for two different projection angles --- a pair that add up to 90 degrees.
Relevant Equations
theta1 +theta2 = 90

v^2 * sin(2theta1)/g = v^2 *sin(2theta2)/g
theta1 = 90- theta2
I substituted that into v^2*sin(2theta1)/g
So I get
v^2*sin(180-2theta2)/g

Now I'm stuck. What do I do next?
 
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You need to go back to the equation. You need to show that the 2 sides of the equation are indeed equal, using some trigonometric identities. You may find this list of identities helpful. https://bitly.com/trigiden
 
Ohh... ok. So it has something to do with the sum and difference identities. Thank you.
 
DeltaForce said:
What do I do next
You ought to know how to simplify sin(180-x), sin(90-x), sin(180+x), and likewise with cos.
 
Yeah. I got it with the trig identities.
 
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