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Browse High School Trigonometry
Stars indicate particularly interesting answers or good places to begin browsing.

Selected answers to common questions:
    DeMoivre's theorem.
    Volume of a tank.

Using the Law of Cosines [05/21/1998]
Given the length of three sides of a triangle, how can I find the angle between any two of the sides?

Using the Laws of Sine and Cosine [9/24/1995]
How do I find the sine and cosine of pi/12?

Using Trig Identities to Simplify [7/26/1996]
How do I simplify ((sin @ - 1)/cos @) - (cos @/(sin @ -1)) ?

Using Trigonometric Identities [05/31/1999]
How can I prove that sin(4x) = 2sin(2x) - 8sin^3(x)cosx ?

Value of Angle DBC [1/23/1996]
Imagine a triangle ABC on which angles B and C are equal to 80...

Vector Angles: Prove A.B = |A||B|cosA [07/13/1998]
I just finished my pre-calc class, and at the end we covered vectors...

Verifying Trigonometric Identities [07/12/2002]
How do you verify a trigonometric identity?

Verify the Identity [04/17/2003]
Verify the identity: (csc x)/(tan x + cot x) = cos x.

Vertices of an Octagon [10/29/1996]
Find the coordinates of the vertices of an octagon with center (0,0) when it is inscribed in a square.

What Is the Length of PR? [01/01/2003]
In a circle of radius 6, a triangle PQR is drawn having QR=8 and PQ=10.

What is the Longest Pole? [04/04/1999]
A metal pole L ft long is pushed on the floor from one corridor into another corridor at a right angle...

What is the Relation between tan and tanh? [08/25/2001]
I want to know the relation between tangent and hyperbolic tangent.

What is Trigonometry? [8/20/1996]
What is trigonometry, and what is it used for?

What's 'Arccos'? [06/17/2001]
I'm trying to write a program in Visual Basic 6 about the distance calculation between two cities.

When to Use Law of Sines or Law of Cosines [02/01/2006]
When do we use the law of sines as opposed to the law of cosines?

Where Will the Runners Meet? [03/29/1999]
Two runners, A and B, start 90 degrees away from each other on a circular track and run at the same speed. If Runner B decides to cut across the track, where will they meet?

Which Side is Longer? [1/27/1995]
You are given a quadrilateral, ABCD, with diagonal DB, angle ADC = 90, angle DBC = 43, angle C = 91, side AD = 9, side DC = 9. Find which is longer AB or AD.

Why does a/SinA = b/SinB = c/SinC? [08/12/1997]
I was just playing aroung with a proof of a triangle and came across the fact that a/SinA = b/SinB = c/SinC. Why?

Why Radians? [12/03/1997]
Why use radians to measure angles over degrees?

Why Use Radians instead of Degrees? [09/25/2001]
Consider Maclaurin's theorem, from which we derive the Taylor series...

Will the Tree Hit the House? [05/18/1999]
A tree is leaning at 70 degrees, our house is 66 1/2 feet away, and the angle from our house to the top of the tree is 40 degrees...

X = TanX [03/21/2001]
Show that x = tanx has an infinite number of solutions.


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