Solve 2cos x+2cos 2x=0 on the interval [0,2pi)

Answers

Answer 1

Answer: $2cosx+2cos2x=0 \n -2sin^2x+2cos^2x+2cosx=0 \n -2(1-cos^2x)+2cos^2x+2cosx=0 \n -2+2cos^2x+2cos^2x+2cosx=0 \n 4cos^2x+2cosx-2=0 \n t=cos x \n 4t^2+2t-2=0 \n \Delta=4+32=36 \n t_1= (-2-6)/(8)=-1 \n t_2= (-2+6)/(8)= (1)/(2) \n cos x=-1 \lor cos x= (1)/(2) \n x=-\pi \lor x= (5\pi)/(3)$

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What is the total cost of a $150.00 necklace if the sales tax is 6.5?

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The best thing to do is to find what 1% is, and you can do this by dividing 150 by 100.
150/100= 1.5
As you're looking for 6.5%, you've got to multiply 1.5 by 6.5
1.5*6.5= 9.75
You've then got to add 9.75 and 150 together
150+9.75= $159.75
Therefore, after the sales tax, the cost of the necklace is $159.75
Hope this helps :)

What is the equation of the line, in general form, that passes through the point (1, 1) and has a y-intercept of 2. possible answers: x - y + 2 = 0
x + y - 2 = 0
x - y - 2 = 0

Answers

To solve this problem we need to know the form of the general equation of the line. That is, y= mx+b where m is the slope and b is the intercept. We are already given the y-intercept (2) our next step is to fin the slope. Substitute the point give (1,1) in the equation y= mx+2 and then solve for m. The slope is then -6. The final equation is y = -x+2 or x + y - 2 = 0

the answer seems to be x+y-2=0

The area of a rectangular park is 3/5 square mile. the length of the park is 7/8 mile. what is the width of the parkshow your work

remember that Area=Length +Width

Answers

Width of a rectangular park is equal to $\boldsymbol{(24)/(35)}$ mile.

Area of a rectangle

Area of a rectangle $=$ Length $*$ Width

Area of a rectangular park $=(3)/(5)$ square mile

Length of a rectangular park $=(7)/(8)$ mile

$(3)/(5)=(7)/(8)*$ Width of a rectangular park

So,

Width of a rectangular park $=(3)/(5)* (8)/(7)$

$=\boldsymbol{(24)/(35)}$

Find out more information about rectangle here:

brainly.com/question/15019502?referrer=searchResults

A = L * W

3/5 = 7/8 * W

divide both sides by 7/8

W = 24/35 of 0.6857

What is the length of BC?
A. 9 units
B. 11 units
C. 15 units
D. 16 units

Answers

Answer:

15units

Step-by-step explanation:

BC is: 5x=5×3=15 units. so,Length of BC=15 units

A direct variation function contains the points (–8, –6) and (12, 9). Which equation represents the function? y = –x

Answers

you multiply by using the formula

x1*x2=y1*y2

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