Find the value of $\mathrm{cos}240\xb0$ .

Mary Hammonds
2021-12-26
Answered

Find the value of $\mathrm{cos}240\xb0$ .

You can still ask an expert for help

enhebrevz

Answered 2021-12-27
Author has **25** answers

Reference angle for 240° is 60°: 240°=180°+60°

$\mathrm{cos}60\xb0=\frac{1}{2}$

As$\mathrm{cos}240\xb0=-\mathrm{cos}60\xb0$ , we have

$\mathrm{cos}240\xb0=-\frac{1}{2}$

As

Rita Miller

Answered 2021-12-28
Author has **28** answers

Write $\mathrm{cos}240\xb0$ as $\mathrm{cos}(180\xb0+60\xb0)$

Using the summation identity:

$\mathrm{cos}\left(180\xb0\right)\mathrm{cos}\left(60\xb0\right)-\mathrm{sin}\left(180\xb0\right)\mathrm{sin}\left(60\xb0\right)$

Using trivial identity:$\mathrm{cos}180\xb0=(-1),\mathrm{cos}60\xb0=\frac{1}{2},\mathrm{sin}180\xb0=0,\mathrm{sin}60\xb0=\frac{\sqrt{3}}{2}$

$=(-1)\times \frac{1}{2}-0\times \frac{\sqrt{3}}{2}$

$=-\frac{1}{2}$

Using the summation identity:

Using trivial identity:

karton

Answered 2022-01-04
Author has **368** answers

The value of

asked 2021-05-19

Find the point on the line

asked 2020-11-26

Match each of the trigonometric expressions below with the equivalent non-trigonometric function from the following list. Enter the appropriate letter(A,B, C, D or E)in each blank

A .$\mathrm{tan}\left(\mathrm{arcsin}\left(\frac{x}{8}\right)\right)$

B .$\mathrm{cos}\left(ar\mathrm{sin}\left(\frac{x}{8}\right)\right)$

C.$\left(\frac{1}{2}\right)\mathrm{sin}\left(2\mathrm{arcsin}\left(\frac{x}{8}\right)\right)$

D.$\mathrm{sin}\left(\mathrm{arctan}\left(\frac{x}{8}\right)\right)$

E.$\mathrm{cos}\left(\mathrm{arctan}\left(\frac{x}{8}\right)\right)$

A .

B .

C.

D.

E.

asked 2021-05-31

Find an equation of the plane. The plane through the points (2, 1, 2), (3, −8, 6), and (−2, −3, 1)

asked 2020-12-24

The prism has a cross-sectional area in the shape of a sector. Calculate:
a. the radius rr cm,

b. the cross-sectional area of the prism,

c. the total surface area of the prism,

d. the volume of the prism

b. the cross-sectional area of the prism,

c. the total surface area of the prism,

d. the volume of the prism

asked 2020-11-07

In quadrant I, drawn a right triangle with one leg on the x-axis and its hypotenuse on the terminal side of drawn in standard position. If

asked 2020-11-06

‘Rewrite the Jofinition “An equilateral triangle has three sides
vrite the definihon fv, biconditional.

asked 2021-06-07

Find, correct to the nearest degree, the three angles of the triangle with the given vertices.

A(1,0,-1), B(5,-3,0), C(1,5,2)

Find$\mathrm{\angle}CAB,\mathrm{\angle}ABC,\mathrm{\angle}BCA$

A(1,0,-1), B(5,-3,0), C(1,5,2)

Find