$MathMaster logo$

MathMaster

Home
general
given cos26 k find cos13

Question

given cos26=k find cos13

93

likes

465 views

Answer to a math question given cos26=k find cos13

$Expert avatar$

4.9

116 Answers

cos(2θ) = 2 \times cos^2(θ) - 1

cos^2(θ) = \frac{(cos(2θ) +1)}{2}

cos^2(13) = \frac {cos(26) +1}{2}

cos^2(13) = \frac{k +1}{2}

\cos\:13\:=\pm\sqrt{\left(\frac{k+1}{2}\right)}}

Frequently asked questions (FAQs)

What is the average of the following data set: 7, 9, 12, 15, 17, 9, 14?

+

Question: What is the antiderivative of the function f(x) = 2x^3 - 5x^2 + 3x - 7 in terms of x?

+

Math question: What is the slope-intercept equation of a line passing through (-3, 4) and (5, -2)?

+

New questions in Mathematics

If we have the sequence: 3, 6, 12, 24 Please determine the 14th term.

What is the amount of interest of 75,000 at 3.45% per year, at the end of 12 years and 6 months?

A book is between 400 and 450 pages. If we count them 2 at a time there is none left over, if we count them 5 at a time there is none left over and if we count them 7 at a time there are none left over, how many pages does the book have?

The Lenovo company manufactures laptop computers, it is known that for every 60 laptops produced, 54 go on the market with the highest quality standards. If a sample of 15 laptops is taken, calculate the probability that: Exactly 2 are not of high quality

[(36,000,000)(0.000003)^2]divided(0.00000006)

To make brine, José buys 1 kg of salt and pays 12 pesos. If he buys 4 kg, they charge him 48 pesos, but for 100 pesos they sell him 9 kg. What is the constant of proportionality?

How many different ways can a psychology student select 5 subjects from a pool of 20 subjects and assign each one to a different experiment?

Credit title that represents a payment order. This model, which emerged in Brazil, can only be issued in two specific situations: in the purchase and sale of commercial products or in the provision of services. Select the correct alternative: Question 6Answer The. Present value B. Promissory note w. Present value d. Duplicate It is. Bill of exchange

Desarrolla (2x)(3y + 2x)5

Find the derivatives for y=X+1/X-1

Convert 5/9 to a decimal

At the dance there are 150 boys the rest are girls. If 65% are girls what is the total amount in the room

Next%C3%B3n%2C+we+are+given+a+series+of+Tri%C3%A1angles+Right%C3%A1angles+%3Cbr%2F%3Ey+in+each+one+of+them+ are+known+2%28two%29+measurements+of+sides.+%3Cbr%2F%3Elet's+determine+all+trigonom%C3%A9tric+ratios.

Calculate the difference between 407 and 27

Calculate the change in internal energy of a gas that receives 16000 J of heat at constant pressure (1.3 atm) expanding from 0.100 m3 to 0.200 m3. Question 1Answer to. 7050J b. 2125J c. None of the above d. 2828J and. 10295 J

The mean of 4 numbers is 5 and the mean of 3 different numbers is 12. What is the mean of the 7 numbers together? Produce an algebraic solution. Guess and check is acceptable.