A selection of free mathematics resources (calculators, exercises, games, quizzes, course reminders) that allow to manipulate the usual trigonometric functions.

## Trigonometric functions : Reminder

### Trigonometric formulas

Here are the main trigonometric formulas that can be used to simplify trigonometric calculations.

• AA x in RR, k in ZZ,
• cos(-x)= cos(x)
• cos(x+2*k*pi)=cos(x)
• cos(pi-x)=-cos(x)
• cos(pi+x)=-cos(x)
• cos(pi/2-x)=sin(x)
• cos(pi/2+x)=-sin(x)
• AA x in RR, k in ZZ,
• sin(-x)= -sin(x)
• sin(x+2*k*pi)=sin(x)
• sin(pi-x)=sin(x)
• sin(pi+x)=-sin(x)
• sin(pi/2-x)=cos(x)
• sin(pi/2+x)=cos(x)
• AA x in RR, k in ZZ,
• tan(-x)= -tan(x)
• tan(x+k*pi)=tan(x)
• tan(pi-x)=-tan(x)
• tan(pi+x)=tan(x)
• tan(pi/2-x)=1/tan(x)
• tan(pi/2+x)=-1/tan(x)
• cos(a-b)=cos(a)*cos(b)+sin(a)*sin(b)
• cos(a+b)=cos(a)*cos(b)-sin(a)*sin(b)
• sin(a-b)=sin(a)*cos(b)-cos(a)*sin(b)
• sin(a+b)=sin(a)*cos(b)+cos(a)*sin(b)
• cos(2a)=(cos(a))^2-(sin(a))^2
• sin(2a)=2*sin(a)*cos(a)
• (cos(a))^2=(1+cos(2a))/2
• (sin(a))^2=(1-cos(2a))/2
• (cos(a))^2+(sin(a))^2=1

## Trigonometric functions : calculators

• arccos : arccosine. The arccos function allows the calculation of the arc cosine of a number. The arccos function is the inverse functions of the cosine function.
• arcsin : arcsine. The arcsin function allows the calculation of the arc sine of a number. The arcsin function is the inverse function of the sine function.
• arctan : arctangent. The arctan function allows the calculation of the arctan of a number. The arctan function is the inverse functions of the tangent function.
• cos : cosine. The cos trigonometric function calculates the cos of an angle in radians, degrees or gradians.
• cosec : cosecant. The trigonometric function sec allows to calculate the secant of an angle expressed in radians, degrees, or grades.
• cotan : cotangent. The cotan trigonometric function to calculate the cotan of an angle in radians, degrees or gradians.
• expand_trigo : trigonometric expansion. The calculator makes it possible to obtain the trigonometric expansion of an expression.
• linearization_trigo : trigonometric linearization. Calculator that allows to linearize a trigonometric expression.
• sec : secant. The trigonometric function sec allows to calculate the secant of an angle expressed in radians, degrees, or grades.
• simplify : Simplify Calculator. Calculator wich can simplify an algebraic expression online.
• simplify_trig : Trigonometric Calculator. Calculator wich uses trigonometric formula to simplify trigonometric expression.
• sin : sine. The sin trigonometric function to calculate the sin of an angle in radians, degrees or gradians.
• tan : tangent. The tan trigonometric function to calculate the tan of an angle in radians, degrees or gradians.