$MathMaster logo$

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)

Question: Find the value of sin(3π/4) - cos(π/6).

+

Question: How would you graph the exponential function y = 3^x on a coordinate plane?

+

What criteria must be satisfied for two triangles to be congruent?

+

New questions in Mathematics

A particular employee arrives at work sometime between 8:00 a.m. and 8:50 a.m. Based on past experience the company has determined that the employee is equally likely to arrive at any time between 8:00 a.m. and 8:50 a.m. Find the probability that the employee will arrive between 8:05 a.m. and 8:40 a.m. Round your answer to four decimal places, if necessary.

Karina has a plot of 5,000 square meters in which she has decided that 60% of it will be used to plant vegetables. Of this part, 12% will be dedicated to planting lettuce. How much surface area of the plot will be used for cultivation?

Given that y = ×(2x + 1)*, show that dy = (2x + 1)" (Ax + B) dx where n, A and B are constants to be found.

The data set (75, 85, 58, 72, 70, 75) is a random sample from the normal distribution No(µ, σ). Determine a 95% two-sided confidence interval for the mean µ .

A regional candy factory sells a guava roll at a price of $48, the monthly fixed costs amount to $125,000 and the variable cost for making a guava roll is $28. Determine: a) The equation of the total income from the production of guava rolls.

Clara usually walks briskly to the farmers' market and it takes her 22 minutes. Today she walked leisurely and it took 61/2 minutes. How much more time than usual did she take to reach the market today?

A merchant can sell 20 electric shavers a day at a price of 25 each, but he can sell 30 if he sets a price of 20 for each electric shaver. Determine the demand equation, assuming it is linear. Consider (P= price, X= quantity demanded)

User Before the election, a poll of 60 voters found the proportion who support the Green candidate to be 25%. Calculate the 90% confidence interval for the population parameter. (Give your answers as a PERCENTAGE rounded to TWO DECIMAL PLACES: exclude any trailing zeros and DO NOT INSERT THE % SIGN) Give the lower limit of the 90% confidence interval Give the upper limit of the 90% confidence interval

Your boss asks you to plan the sample size for a randomized, double-blind, controlled trial in the clinical development of a cure for irritable bowl disease. Current standard treatment shall be compared with a new treatment in this trial. The S3-guideline of AWM demonstrated a mean change of the summary score of the validated health related quality of life questionnaire at 8 weeks of 16 with standard deviation 23 under standard treatment. You quote the drop-out rate of 11% from literature (previous phase of clinical development). Your research yielded a clinically important effect of 4 that has been found to be the Minimal Clinically Important Difference (MCID). In order to demonstrate superiority of the new treatment over standard of care, you assume that the change in of the summary score of the validated health related quality of life questionnaire follows a normal distribution, and that the standard deviation is the same for both treatments. How many patientes would one need to recruit for the trial to demonstrate the clinically interesting difference between treatments at significance level 5% with 95% power?

Solve equations by equalization method X-8=-2y 2x+y=7

(a) List the set of possible rational zeros of the polynomial function F(x) = 2x3 - 11x2 + 13x - 4. (b) Find all rational zeros of F(x). Only do part B

To find the increased amount on a standard term deposit with the following conditions: starting amount: BGN 13000, type of deposit: annual, annual compound interest rate: 1.4%, after 4 years;

Write an expression using compatible numbers that can be used to estimate the quotient 629\86

Total Users with an active Wise account = Total Active Users + Total Users who haven’t transacted Total Active Users = Total MCA Users + Total Send Users = Total New Users + Retained Users Total New Users = New Send Users + New MCA Users Total MCA Users = New MCA Users + Retained Users who transacted this month via MCA Total Send Users = New Send Users + Retained Users who transacted this month via Send Send CR = Total Send Users / Total Users with an active Wise account MCA CR = Total MCA Users / Total Users with an active Wise account New Send CR = New Send Users / New Profiles Created in Month New MCA CR = New MCA Users / New Profiles Created in Month We have recently witnessed a drop in MCA conversion, but send user conversion is stable, can you help explain why?

The blood types of individuals in society are as follows: A: 30%, B: 25%, AB: 20%, 0: 25%. It is known that the rates of contracting a certain disease according to blood groups are as follows: A: 7%, B: 6%, AB: 7%, 0: 4%. Accordingly, if a person selected by chance is known to have this disease, what is the probability of having blood group O?

Arturo had hospitalization expenses of $8,300. Your policy for medical expenses Seniors have a deductible of $500 and expenses are paid at a 20% coinsurance. These are the first expenses ever this year, how much will Arturo have to pay in your bill for hospitalization expenses?

g(x)=3(x+8). What is the value of g(12)

If the area of a circle is 75.7ft2, what is the radius? Give the answer in metres. Round answer to 2 decimal places and enter the units.