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cmkluza
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I'm realizing now how much I need to know the exact values of various trigonometric functions, as shown in various trig tables. Memorizing is pretty arduous, and I'd prefer to understand it, so how can I learn all of these?
DrClaude said:A long long time ago, my math teacher made us build our own trigonometric circles. Having a geometrical representation really helped me, and the values of the functions have stuck with me ever since.
It's even more than that. Consider for instance π/6 (30°): you get halfway up on the y axis, so obviously sin π/6 = 1/2. Likewise, for π/4, you can see it as building a square of side 1/2 (along x and y), so the diagonal is (according to Pythagoras) ##\sqrt{(1/2)^2 + (1/2)^2} = 1/\sqrt{2} = \sqrt{2}/{2}##. All of these geometric equivalents have really helped me.cmkluza said:Thanks! I guess I'd forgotten that these circles existed. Does this mean that if I memorize the important angles/values from the first quadrant I can use the identities of -sin(θ) = sin(-θ) and cos(-θ) = cos(θ) to figure out the values in each other quadrant?
I realize that this might not be as clear as it can be. Rather, take the radius as the hypotenuse of a right triangle with two equal sides of length ##a## (along the x and y axes), so by Pythagoras ##2a^2 = 1 \Rightarrow a = 1/\sqrt{2}##, thus ##\cos \pi/4 = \sin \pi/4 = \sqrt{2}/2##.DrClaude said:Likewise, for π/4, you can see it as building a square of side 1/2 (along x and y), so the diagonal is (according to Pythagoras) ##\sqrt{(1/2)^2 + (1/2)^2} = 1/\sqrt{2} = \sqrt{2}/{2}##.
And once you have those, you can use them to find the values for some other angles. For example,Erland said:Easiest way is to use to draw a half square and a half equiliteral triangle, and use the Pythagorean theorem to obtaim sin, cos and tan for the angles in tjose triangles, i.e. 45, 30 and 60 degrees.
Erland said:Easiest way is to use to draw a half square and a half equiliteral triangle, and use the Pythagorean theorem to obtaim sin, cos and tan for the angles in tjose triangles, i.e. 45, 30 and 60 degrees.
The most common trigonometric functions are sine, cosine, tangent, cotangent, secant, and cosecant.
Exact values for trigonometric functions are important because they allow for more precise calculations and can be used to solve a variety of mathematical problems.
One way to remember the exact values for trigonometric functions is to use mnemonic devices, such as the phrase "SOH CAH TOA" to remember the ratios for sine, cosine, and tangent in a right triangle.
Practicing with different examples and using trigonometric tables or calculators can help improve your ability to find exact values for trigonometric functions. Also, understanding the unit circle and the relationships between different trigonometric functions can be beneficial.
Some tips for quickly finding exact values for trigonometric functions include memorizing common angles and their corresponding values, using symmetry and reference angles, and simplifying fractions to reduce the number of calculations needed.