Question

A) What is the value of cos x?

b) What is the value of cos z?
Give your answers as fractions in their
simplest forms.

Answer 1

The value of cos x is 21.79 degrees

The value of cos z is 120 degrees

How can angle x be calculated?

Trigonometry is the area of mathematics that deals with particular angle functions and how to use them in computations. In trigonometry, an angle can have six common functions. The terms sine (sin), cosine (cos), tangent (tan), cotangent (cot), secant (sec), and cosecant (csc) are their names and abbreviations.

Using cosine rule, angle x In the triangle can be calculated

`cos A =( (b^(2) + c^(2) - a^(2) ))/( 2bc)`

For the angle x

`cos x = (7^(2) +5^(2) -3^(2) )/(2 * 7 * 5)`

`cos x =(65)/(70)`

x = arc cos ( 0.9286 )

x = 21.79 degrees

`cos z = (3^(2) +5^(2) -7^(2) )/(2 * 3 * 5)`

=-15/30

=-0.5

x = arc cos ( -0.5)

x = 120 degrees