0
How would you solve the following over the interval 0 is less than or equal to x which is less than 2pi here's the problem 2cos squared x minus 5cos x minus 3 equals 0?
Wiki User
∙ 12y ago
2 cos2(x) - 5 cos(x) - 3 = 0
To save some writing, let's temporarily write "Q" instead of "cos(x)".
2 Q2 - 5 Q - 3 = 0
Factor the trinomial:
(2 Q + 1) (Q - 3) = 0
2Q + 1 = 0
2Q = -1
Q = - 1/2
Q - 3 = 0
Q = 3
Recalling that 'Q' is a cosine of an angle, (Q = -1/2) is the root that makes sense,
because the cosine of a real angle can never be 3 .
So now, we can get rid of 'Q' and go back to the cosine:
cos(x) = -1/2
x = 120 degrees
x = 240 degrees
Wiki User
∙ 12y ago
Add your answer:
Earn +20 pts
What multiplication problem equals 144?
12 squared.
What is Galileo's formula with distance accleraction and time?
distance equals initial velocity times change in time interval plus half of accerlation plus time interval squared
Which if the following is a factor b squared plus bc munus 2c squared equals?
(b + 2c)(b - c)
How do you solve 16t squared minus 9 equals 0?
Solve this problem -x squared -40x- 80 =0
How do you solve X squared minus four for x equals 3?
Your Problem: X - 4 = ?Current Problem: 3 [squared] - 4 = ?How: When a numbered is squared, it means you multiply it against itself. So, 3 squared equals 3x3.3x3 = 9So, you would then take 9 and minus it by 4, which would than equal 5.Answer:3 [squared] - 4 = 5or9 - 4 = 5
Find the average value of the function on the given interval fx equals 2x to the power of3 open parentheses 1 plus x squared closed to the fourth power?
You need to clarify the function AND provide an interval.
If you have a equals 3.14 times the radius squared what do you do if the problem gives you the diameter?
Cut the diameter in half.
When a squared plus b squared equals c squared what is the square root of the square root of the square root of a squared squared squared plus b squared squared squared?
Since a squared plus b squared equals c squared, that is the same as c equals the square root of a squared plus b squared. This can be taken into squaring and square roots to infinity and still equal c, as long as there is the same number of squaring and square roots in the problem. Since this question asks for a and b squared three times, and also three square roots of a and b both, they equal c. Basically, they cancel each other out.
What number squared equals 30?
5.477225575 squared equals 30.
What equals 121 when its squared?
The number that equals 121 when squared is 11.
What is a squared plus b squared equals c squared when a equals 2 and c equals 6?
b = sqrt32 or 4 root 2
Does 6xy-8xy equals -2x squared y squared?
No, it equals -2xy. lrn2math
