$MathMaster logo$

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

114 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 value of the constant 'c' in the function f(x) = c, if f(4) = 9?

+

What are the solutions to the quadratic equation 4x^2 - 7x + 3 = 0?

+

What is the quadratic formula used to solve equations with the form ax^2 + bx + c = 0?

+

New questions in Mathematics

Students Ana Beatriz and Paula decided to register on a website with exercises to study for upcoming simulations, but to register on this website, they need to choose a password consisting of five characters, three numbers and two letters (capital letters). or lowercase). Letters and numbers can be in any position. They know that the alphabet is made up of twenty-six letters and that an uppercase letter differs from a lowercase letter in a password. What is the total number of possible passwords for registering on this site?

Use the digits of 1,9,2,3 to come up with all the numbers 98 and 95

Given the vectors: a = (2m – 3n, 4n – m) and b = (2, -3), find the values of m and n that make: a = 5 b.

(6.2x10^3)(3x10^-6)

(3x^(2) 9x 6)/(5x^(2)-20)

Suppose 56% of politicians are lawyers if a random sample of size 564 is selected, what is the probability that the proportion of politicians who are lawyers will differ from the total politicians proportions buy more than 4% round your answer to four decimal places

Equivalent expression of the sequence (3n-4)-(n-2)

Determine the minimum degree that an algebraic equation can assume knowing that it admits 2 as a double root and -i as a triple root

If 0101, what is the binary representation of the 4x16 decoder output?

Prove that it is not possible to arrange the integers 1 to 240 in a table with 15 rows and 16 columns in such a way that the sum of the numbers in each of the columns is the same.

The average number of babies born at a hospital is 6 per hour. What is the probability that three babies are born during a particular 1 hour period?

Find all real numbers x that satisfy the equation \sqrt{x^2-2}=\sqrt{3-x}

During a fishing trip Alex notices that the height h of the tide (in metres) is given by h=1−(1/2)*cos(πt/6) where t is measued in hours from the start of the trip. (a) Enter the exact value of h at the start of the trip in the box below.

Solve the equation: sin(2x) = 0.35 Where 0° ≤ x ≤ 360°. Give your answers to 1 d.p.

In an orchard there are 360 trees and they are distributed in 9 rows with the same number of trees in each row. 2 are rows of orange trees, 4 of apple trees and the rest are of pear trees. What fraction of the trees in the orchard are of each type of fruit tree? How many trees of each type are there?

prove that for sets SS, AA, BB, and CC, where AA, BB, and CC are subsets of SS, the following equality holds: (A−B)−C=(A−C)−(B−C)

Square root of 169 with steps

Find the orthogonal projection of a point A = (1, 2, -1) onto a line passing through the points Pi = (0, 1, 1) and P2 = (1, 2, 3).

An export company grants a bonus of $100,000 pesos to distribute among three of its best employees, so that the first receives double the second and the latter receives triple the third. How much did each person receive?