Gauss' method for addition relies on the fact that you can 'pair' certain numbers together. Look at the example:
1+2+3+4+5+6+7+8+9+10
We could manually add all these together from left to right but a clever way to think about this is if we add together the ends of the sum (10+1) we get 11. If we then move one in from the ends and add these (2+9) we also get 11. This means that 1+2+...+9+10 is the same as 11+11+...+11+11.
Because each 2 numbers adds to 11 we know the total number of 11's we have to add together is the length of the sum divided by 2. In our case 5 (10 ÷ 2). We need to add 5 lots of 11 to get our answer. This is the same as 11 × 5 which is easily seen to be 55.
(If you add the 10 numbers together on a calculator you'll see 1+2+3+4+5+6+7+8+9+10 = 55) so this method really makes it a lot quicker.
Looking at your sequence, if we pair the ends together we get 401 (400+1) and we multiply this by the length of the sequence divided by 2. In your case, 200 (400 ÷ 2).
So the sum of all the numbers from 1 to 400 must be 401 × 200 = 80,200.
Remember the steps:
1. Pair the ends together and add them
2. Times this number by the length of the sequence halved
Hope this helps.
By using trigonometric relations, we will find that:
sin(θ) = (√33)/7 = √(33/49)
<h3>How to find the value of the sine?</h3>
Remember that for a right triangle, we have the relations:
cos(a) = (adjacent cathetus)/(hypotenuse)
sin(a) = (opposite cathetus)/(hypotenuse).
Here we know that:
cos(θ) = 4/7
Then we can say that we have a triangle with an adjacent cathetus of 4 units and a hypotenuse of 7 units. Now we need to find the other cathetus.
opposite cathetus = √(7^2 - 4^2) = √33
Then we can write:
sin(θ) = (√33)/7 = √(33/49)
If you want to learn more about trigonometry.
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Answer:
x=40 degrees
Step-by-step explanation:
there is 180 degrees in half a circle,and 180-100=80
and because there are 2 x values on either side you divide that 80 by 2 which gives you 40.
Answer:
16 ft
Step-by-step explanation:
One of the other three sides is 12 ft. After that fence is subtracted from the total, there are 32 ft of fence left for the other two sides of the rectangle. That allows those sides to be 32 ft/2 = 16 ft long.
The rectangle can be 12 ft by 16 ft. The longer dimension is 16 ft.