Sin Cos Formulas

Sin and Cos are basic trigonometric functions that tell about the shape of a right triangle, so the Sin Cos formulas are the basic ones in trigonometry.

  • Sin A = Perpendicular/Hypotenuse
  • Cos A = Base/Hypotenuse
  • Sin Cos Formulas

    Basic Trigonometric Identities for Sine and Cos

    These formulas help in giving a name to each side of the right triangle and these are also used in trigonometric formulas for class 11. Let’s learn the basic sin and cos formulas.

    • cos2(A) + sin2(A) = 1

    If A + B = 180° then:

    • sin(A) = sin(B)
    • cos(A) = -cos(B)

    If A + B = 90° then:

    • sin(A) = cos(B)
    • cos(A) = sin(B)

    Sine and Cosine Formulas

    To get help in solving trigonometric functions , you need to know the trigonometry formulas.

  • Double and Triple angle formulas

    • Sin 2A = 2Sin A Cos A
    • Cos 2A = Cos2A – Sin2A = 2 Cos2 – 1 = 1- Sin2A
    • Sin 3A = 3Sin A – 4 Sin 3A
    • Cos 3A = 4 Cos3A – 3CosA
    • Sin4A = 4 Cos3A . Sin A – 4Cos A. Sin 3A
    • CosA = Cos4A – 6Cos2A.Sin2A +Sin4A
    • Sin2A = 1Cos(2A)/2
    • Cos2A =1+Cos(2A)/2

    Sum and Difference of Angles

    • sin(A + B) = sin(A).cos(B) + cos(A)sin(B)
    • sin(B)sin(A−B)=sin(A)⋅cos(B)−cos(A)⋅sin(B)
    • 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+C)=sinA⋅cosB⋅cosC+cosA⋅sinB⋅cosC+cosA⋅cosB⋅sinC−sinA⋅sinB⋅sinC
    • cos(A+B+C)=cosA⋅cosB⋅cosC−sinA⋅sinB⋅cosC−sinA⋅cosB⋅sinC−sinA⋅cosB⋅sinC−cosA⋅sinB⋅sinC
    • Sin A + Sin B = 2Sin(A+B)/2Cos(AB)/2
    • Sin A – Sin B = 2Sin(AB)/2Cos(A+B)/2
    • Cos A + Cos B = 2Cos(A+B)/2Cos(AB)/2
    • Cos A + Cos B = -2Sin(A+B)/2Sin(AB)/2