ftfd54ertre765r ftfd54ertre765r

11-08-2016
Mathematics

contestada

2cos2θ−cosθ−1=0 for −180°≤θ≤180°
I don't get how it is solved

Respuesta :

11-08-2016

Hello,

cos 2t=2cos²t-1

2cos 2t -cos t-1=
==>2(2cos² t -1)-cos t-1=0
==>4cos² t -cos t -3=0
Δ=(1+4*4*3=49=7²
cos t= (1+7)/8 or cos t=(1-7)/8
cos t =1 or cos t=-3/4

t=0° or t=138.590377...°

Answer Link

Otras preguntas

Replace the bolded noun with the appropriate pronoun. Although Marshall and Trevor wanted to see the latest comedy movie, THE MOVIES was sold out. A)it B) he C)

1. Select the answer that best completes the sentence. El sofá está en __________. A) el patio B) la sala C) la cocina D) el garaje 2. Select the answer that

What do Impressionist artworks by Mary Cassatt depict?

1. When an activist decides to use a song, speech, or video to communicate his message, he is using ________________________ to reach his audience. A. a clear

What is wx zy=c solving for y?

-1/9 divided by 3/4 -4/27 -1/12 1/12 4/27

;-; What does this mean ;-;

What was the purpose of the three fifths compromise?

A _____ maintains limited liability but offers more flexibility in terms of tax treatment than other forms of business ownership.

Is it important for a writer to include voice and point of view in writing because... Plz help