Question

what is trignometry and define with example

Answer 1

tri  = three
gono= angle 
metry= measurement

Answer 2

Use trigonometry in a sentence. noun. Trigonometry is defined as the branch of math that deals with calculations related to the sides and angles of triangles. An example of trigonometry is what architects use to calculate distances.


Questions 2:

x is in quadrant 3, approximate sin (2 x) if cos (x) = - 0.2. Round your answer to two decimal places.

Solution to Question 2:

sin (2x) may be calculated using the double angle trigonometric identity

sin (2x) = 2 sin (x) cos (x)

cos x is given, we need to find sin x using the identity sin 2x + cos 2x = 1 and noting that x is in quadrant 3 where sin x is negative

sin x = - SQRT[ 1 - (- 0.2)2 ]

sin (2x) is now given by

sin (2x) = 2 [ - SQRT[ 1 - (- 0.2)2 ] ] (-0.2)

= 0.39