0
What is the exact value using a sum or difference formula of the expression cos 11pi over 12?
Wiki User
∙ 12y ago
11pi/12 = pi - pi/12
cos(11pi/12) = cos(pi - pi/12)
cos(a-b) = cos(a)cos(b)+sin(a)sin(b)
cos(pi -pi/12) = cos(pi)cos(pi/12) + sin(pi)sin(pi/12)
sin(pi)=0
cos(pi)=-1
Therefore, cos(pi -pi/12) = -cos(pi/12)
pi/12=pi/3 -pi/4
cos(pi/12) = cos(pi/3 - pi/4)
= cos(pi/3)cos(pi/4)+sin(pi/3) sin(pi/4)
cos(pi/3)=1/2
sin(pi/3)=sqrt(3)/2
cos(pi/4)= sqrt(2)/2
sin(pi/4) = sqrt(2)/2
cos(pi/3)cos(pi/4)+sin(pi/3) sin(pi/4)
= (1/2)(sqrt(2)/2 ) + (sqrt(3)/2)( sqrt(2)/2)
= sqrt(2)/4 + sqrt(6) /4
= [sqrt(2)+sqrt(6)] /4
Therefore, cos(pi/12) = (sqrt(2)+sqrt(6))/4
-cos(pi/12) = -(sqrt(2)+sqrt(6))/4
cos(11pi/12) = -(sqrt(2)+sqrt(6))/4
Wiki User
∙ 12y ago
Add your answer:
Earn +20 pts
How is using a formula similar to evaluating an expression?
Beacause with a formula you are finding out a problem. Just like evaluating means to find out or to solve.
How do you factor this expression completely 9a4 - b2?
You can start by using the formula for the difference of two squares. Actually, after that I don't think you can factor it any further.
Proof of the derivative of the cosecant function?
Express the cosecant in terms of sines and cosines; in this case, csc x = 1 / sin x. This can also be written as (sin x)-1. Remember that the derivative of sin x is cos x, and use either the formula for the derivative of a quotient (using the first expression), or the formula for the derivative of a power (using the second expression).
How do you solve x 52 x - 22 37 using the quadratic formula?
With great difficulty because it is not a quadratic equation or even a quadratic expression.
What adds up -13 but multiplies to 18?
To 3 decimal places the numbers are about -1.576 and -11.424 but it's quite possible to find exact their exact values by using the quadratic equation formula
How many the expression x3-8 be weritten using difference of cubes?
11
How is using a formula similar to evaluating an expression?
Beacause with a formula you are finding out a problem. Just like evaluating means to find out or to solve.
How do you factor this expression completely 9a4 - b2?
You can start by using the formula for the difference of two squares. Actually, after that I don't think you can factor it any further.
Whats the difference between an algebraic expression and a verbal expression?
The term "verbal expression" in mathematical terms refers to a math phrase or statement that uses words or letters instead of using numbers. An example of this might be "Three divided by two" instead of "3/2."
How do you copy a formula using relative and absolute cell addresing?
When copying a formula using absolute cell addressing the formula is left in it's exact stage. No changes are made, not even symbols excluded or included. The formula stays in it's original form. When using relative cell addressing to copy a formula the formula needs to be copied without any types of symbols.
What is a sentence using the word binomial?
The binomial expression (x+y)^2 can be expanded using the formula x^2 + 2xy + y^2.
The formula for ordinary interest using exact time is?
The formula for simple (ordinary) interest on a bank deposit is Deposit Amount x Rate x Time (# of days) on Deposit.
The elements that make up a compound and the exact number of atoms of each element in a unit of the compound can be?
determined using the chemical formula of the compound. The chemical formula provides the type and ratio of elements present in a compound. After determining the chemical formula, one can calculate the exact number of atoms of each element in a unit of the compound using stoichiometry.
Proof of the derivative of the cosecant function?
Express the cosecant in terms of sines and cosines; in this case, csc x = 1 / sin x. This can also be written as (sin x)-1. Remember that the derivative of sin x is cos x, and use either the formula for the derivative of a quotient (using the first expression), or the formula for the derivative of a power (using the second expression).
How do you solve x 52 x - 22 37 using the quadratic formula?
With great difficulty because it is not a quadratic equation or even a quadratic expression.
What adds up -13 but multiplies to 18?
To 3 decimal places the numbers are about -1.576 and -11.424 but it's quite possible to find exact their exact values by using the quadratic equation formula
How is accleration calculated?
By using the basic definition of acceleration, as (difference of velocity) divided by (time). In cases where the acceleration can be expected to change over time, to get the instantaneous acceleration, you need the limit of this expression, in other words, dv/dt.By using the basic definition of acceleration, as (difference of velocity) divided by (time). In cases where the acceleration can be expected to change over time, to get the instantaneous acceleration, you need the limit of this expression, in other words, dv/dt.By using the basic definition of acceleration, as (difference of velocity) divided by (time). In cases where the acceleration can be expected to change over time, to get the instantaneous acceleration, you need the limit of this expression, in other words, dv/dt.By using the basic definition of acceleration, as (difference of velocity) divided by (time). In cases where the acceleration can be expected to change over time, to get the instantaneous acceleration, you need the limit of this expression, in other words, dv/dt.
