2cosx=2sin2x. Sin2x is an identity for 2sinxcos. So 2[2sinxcosx] gives you 4sinxcosx. 2cosx=4sinxcosx. Divide 2cosx on both sides and gives you 2sinx=0 and divide again, sinx=0. Sinx is 0 at 0 and 360 degrees, or pi and 2pi. So thats what x would be. 0,360,pi,2pi.
Answer:
Step-by-step explanation:
![\sqrt{5} \times \sqrt{10} \\ = \sqrt{5} \times \sqrt[]{5} \times \sqrt{2} \\ = 5\sqrt{2}](https://tex.z-dn.net/?f=%20%5Csqrt%7B5%7D%20%20%5Ctimes%20%20%5Csqrt%7B10%7D%20%20%5C%5C%20%20%3D%20%20%5Csqrt%7B5%7D%20%20%5Ctimes%20%20%5Csqrt%5B%5D%7B5%7D%20%20%5Ctimes%20%20%5Csqrt%7B2%7D%20%20%5C%5C%20%20%20%3D%205%5Csqrt%7B2%7D%20)
<h3>Hope it is helpful....</h3>
Alright! So to solve these questions, you need to find out the difference. You can use ratios to solve this. For example, question #25:
A class had 30 pupils at the beginning of this school term, but now has 5 more pupils. What is the percent of increase?
The question is basically asking how much 5 is in ratio to 30. So just divide 5 (the given amount) by 30 (the total amount). The answer is 0.16, or 16%
Dana can type 90 words per minute.
Since, 1 minute = 
hours
Therefore, number of words she can type = 
= 90×60
= 5400 words per hour
If she types 
words in 'x' hours.
Number of words Dana types with the given speed in 'x' hours = Speed of typing × Time
= 
Therefore, 
hours
Therefore, Dana types words in 48.15 hours.
Learn more,
brainly.com/question/621754
