please help me means tell me about trigonometry according to class 9 because tomorrow is my test
Answers
formula;
By using a right-angled triangle as a reference, the trigonometric functions or identities are derived: sin θ = Opposite Side/Hypotenuse. sec θ = Hypotenuse/Adjacent Side. cos θ = Adjacent Side/Hypotenuse.
calculation of sin cos tan
The sine of the angle = the length of the opposite side. the length of the hypotenuse.
The cosine of the angle = the length of the adjacent side. the length of the hypotenuse.
The tangent of the angle = the length of the opposite side. the length of the adjacent side.
what is meant by trigonametry
Trigonometry is the branch of mathematics which deals with the measurement of sides and angles of a triangle and the problems allied with angles. The ratios of the sides of a triangle with respect to its acute angle are called Trigonometric ratios
List of Trigonometry Formulas
The Trigonometric formulas or Identities are the equations which are true in the case of Right-Angled Triangles. Some of the special trigonometric identities are given below –
Pythagorean Identities
sin²θ + cos²θ = 1
tan2θ + 1 = sec2θ
cot2θ + 1 = cosec2θ
sin 2θ = 2 sin θ cos θ
cos 2θ = cos²θ – sin²θ
tan 2θ = 2 tan θ / (1 – tan²θ)
cot 2θ = (cot²θ – 1) / 2 cot θ
Sum and Difference identities-
For angles u and v, we have the following relationships:
sin(u + v) = sin(u)cos(v) + cos(u)sin(v)
cos(u + v) = cos(u)cos(v) – sin(u)sin(v)
tan(u+v) = tan(u) + tan(v)1−tan(u) tan(v)
sin(u – v) = sin(u)cos(v) – cos(u)sin(v)
cos(u – v) = cos(u)cos(v) + sin(u)sin(v)
tan(u-v) = tan(u) − tan(v)1+tan(u) tan(v)
If A, B and C are angles and a, b and c are the sides of a triangle, then,
Sine Laws
a/sinA = b/sinB = c/sinC
Cosine Laws
c2 = a2 + b2 – 2ab cos C
a2 = b2 + c2 – 2bc cos A
b2 = a2 + c2 – 2ac cos B