The cosine repeats itself every 360 degrees, and it mirrors at 0 and 180 degrees. It inverts around 90 and 270.
So without using a calculator, you can tell that:
cos(520)=cos(520-360)=cos(160)
cos(160) = cos(180-20) = cos(180+20) = cos(200)
cos(160) is NOT equal to cos(20), it would be -cos(20).
cos(160) = -cos(20) = -cos(-20)
So C is the only one unequal.
Answer:
pi/3, 5pi/3
Step-by-step explanation:
We can see that when cosine is at 1/2, the angle measures are pi/3 degrees and 5pi/3 degrees. You can use a unit circle to find this. You can also find arccos(1/2), but that will only give you the value pi/3, not 5pi/3.
We can plug these in to find that they are indeed equal to 1/2.
Answer:
selecting one item? If you mean each color:
40% chance for a red marble / 2/5 chance
60% chance for a blue marble / 3/5 chance
Step-by-step explanation:
Because there are 12 blue marbles and 8 red marbles, we would total them to see how many marbles there are in total. There are 20 in total, but to find the probability, if we put all 20 marbles in a bag (blue and red), and we picked a marble at random, there are 8 red marbles and 12 blue marble in that bag. The probability that I will choose red marbles is 8/20 (or 8 red marbles out of 20 total marbles), and for blue marbles, it would be 12/20 (or 12 blue marbles out of 20 total marbles). Simplify both expression to 2/5, and 3/5 respectively. Finally, if you need percentage, just multiply the denominator by 5 to get it to a hundred, and do the same to the numerator. This way you don't change the value of the expression.