tyjae1601 tyjae1601

07-06-2019
Mathematics

contestada

If cos x = −6/7, and 90° < x < 180°, what is cos⁡(2x)?

Respuesta :

LammettHash LammettHash

07-06-2019

Recall the double angle identity:

[tex]\cos2x=\cos^2x-\sin^2x=2\cos^2x-1[/tex]

Then

[tex]\cos2x=2\left(-\dfrac67\right)^2-1=\dfrac{23}{49}[/tex]

Answer Link

Otras preguntas

Which situation can be modeled by the inequality 5 + 10w ≥ 45? A. You start with $5 and save $10 a week until you have at least $45. B. You start with 5 basebal

Identify and calculate the area and perimeter for this polygon.

The number of days per week worked by husbands in the United States in the early 1990s had mean 5.2 and standard deviation 0.7. (a) Assuming each husband report

Complete the sentences with por or para. 1. Fui a comprar frutas ____ (instead of) mi madre. para por 2. Fui a comprar frutas ____ (to give to) mi madre. para

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!HELP!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! In the equation y + 4 = -204, what is the next step in the equation solving se

A normal distribution has a standard deviation equal to 39. What is the mean of this normal distribution if the probability of scoring above x = 209 is 0.0228?

Question 1 2 pts Simon has decided to support his company's efforts to distribute information to customers via a catalog that will be shipped to their homes. Wh

A pharmaceutical company receives large shipments of aspirin tablets. The acceptance sampling plan is to randomly select and test 47 tablets, then accept the w

Evaluate 13 - 0.75w + 8x when w = 12 and x = 0.5

The information above describes the real GDP per capita for a country for the period from 1985 through to 2001. If a new business cycle began in 1985, how long