TrigCheatSheet FormulasandIdentities TangentandCotangentIdentities tan( ) = sin( ) cos( ) cot( ) = cos( ) sin( ) ReciprocalIdentities csc( ) = 1 sin( ) sin( ) = Sin, cos, and tan are trigonometric ratios that relate the angles and sides of right triangles. Sin is the ratio of the opposite side to the hypotenuse, cos is the ratio of the adjacent side to the hypotenuse, and tan is the ratio of the opposite side to the adjacent side. The graph of tangent is periodic, meaning that it repeats itself indefinitely. Unlike sine and cosine however, tangent has asymptotes separating each of its periods. The domain of the tangent function is all real numbers except whenever cos⁡(θ)=0, where the tangent function is undefined. This occurs whenever . This can be written as θ∈R What is tan 2 in terms of sin and cos? Since tan x can be expressed as the ratio of sine function and cosine function, therefore we can write tans square x as the ratio of sin square x and cos square x, therefore we have tan^2x = sin^2x / cos^2x. Also, we know that tan x is the reciprocal of cot x, therefore we can write tan^2x = 1/cot^2x. For memorising cos 0°, cos 30°, cos 45°, cos 60° and cos 90°. Cos is the opposite of sin. We should learn it like. cos 0° = sin 90° = 1. cos 30° = sin 60° = √3/2. cos 45° = sin 45° = 1/√2. cos 60° = sin 30° = 1/2. cos 90° = sin 0° = 0. So, for cos, it will be like. Indeed, we know that $$1.5 = \cot\theta = \frac{\cos\theta}{\sin\theta}$$ hence $$1.5\sin\theta = \cos\theta.$$ Squaring both sides we have $$2.25\sin^2\theta = \cos^2\theta$$ and since $\cos^2\theta = 1-\sin^2\theta$ we have $$\begin{align*} 2.25\sin^2\theta &= 1-\sin^2\theta\\ 2.25\sin^2\theta + \sin^2\theta &= 1\\ 3.25\sin^2\theta &= 1. This video is a quick introduction to sine, cosine, and tangent. It teaches you how to find the values of sine, cosine, and tangent if you are told the leng cos(4A) − sin(2A) = 0. Here the “angles”, the arguments to the trig functions, are 4A and 2A. True, you want to solve for A ultimately. But if you can solve for the angle 4A or 2A, it is then quite easy to solve for the variable. As you see, that equation involves two functions (sine and cosine) of two angles (4A and 2A). You need to get 6÷2(1+2) = ? - https://youtu.be/jLaON6KM-pQ9 - 3 ÷ 1/3 + 1 = ? Viral Problem - https://youtu.be/yIqrDEkbOPAFlat Earth Debunked - https://youtu.be/wACpfy2DgYE All three angles are 60 degrees (pi/3). Cut it into two right triangles and you get an angle of 30 degrees (pi/6). That also means that the opposite side is going to be exactly half of the hypotenuse. In a unit circle that means that sin=1/2. From there we can work out cos=sqrt3/2. dOM4cb.