The value of cos(x-pi) is equal to -cosx. This can be done using the trigonometric formulas of compound angles. In this post, we will learn how to simplify cos(pi-x) and cos(x-pi). We will use the following formula on compound angles to find cos(pi-x) and cos(x-pi). $\cos(a-b)=\cos a \cos b +\sin a \sin b$ $\cdots (\star)$ … Read more
In this post, we will find the value of sin 75 degree, cos 75 degree, and tan 75 degree. They are very important in Trigonometry. Using their values, we are able to find the trigonometric values of many angles. We will now find the value of sine 75 degree. Value of sin 75 Answer: The … Read more
Note that the cosine function cos(x) is a trigonometric function. Here, we will learn about the domain, range, and period of cos(x). Domain of cos x One knows that for any value of x, the cosine function cos(x) is defined. Thus, by the definition of the domain of a function, we can say that the … Read more
The sine function sin x is a trigonometric function. In this post, we will learn about the domain, range, and period of sin x. Domain of sin x We know that the sine function sin x is computable for any real number x. Thus, the domain of sin x is the set of all … Read more
The formula of cos(a+b)cos(a-b) is given by cos(a+b)cos(a-b) = cos2a -sin2b. In this post, we will establish the formula of cos(a+b) cos(a-b). Note that cos(a+b) cos(a-b) is a product of two cosine functions. We will use the following two formulas: cos(a+b) = cos a cos b – sin a sin b …(i) cos(a-b) = cos a … Read more
In this post, we will establish the formula of sin(a+b) sin(a-b). Note that sin(a+b) sin(a-b) is a product of two sine functions. We will use the following two formulas: sin(a+b) = sin a cos b + cos a sin b …(i) sin(a-b) = sin a cos b – cos a sin b …(ii) Formula of sin(a+b) … Read more
One can define equations involving trigonometric functions. These equations are called trigonometric equations. In this post, we will learn about the general solutions of the trigonometric equations: sin x=0, cos x =0, and tan x =0. Solution of sin x =0 Solve $\sin x =0$. The general solutions of the equation $\sin x =0$ are … Read more
The values of sin 15°, cos 15°, and tan 15° are very important in the theory of Trigonometry. We will find their values in this post. Let us now find the value of sin 15 degree. Value of sin 15 We will evaluate the value of $\sin 15$ using the formula of the compound angles of … Read more
Here you will find out a complete topic on trigonometry. Values of sin 15, cos 15, and tan 15 Solutions of sin x =0, cos x =0, and tan x =0 Cos3x Formula & Proof Tan2x Formula in terms of tanx, sinx, cosx Sin3x Formula in terms of sinx Simplify 1-sin^2(x) Simplify cos(sin^{-1}x) Simplify sin(cos^{-1}x)