What does sin180 and cos180 equal
sin180°=cos0°=0
cos180°=sin0°=1
Sum: SN = 1 * n + 2 * (n-1) + 3 * (n-2) + +n*1
Let me have a try
Sn+1=1*(n+1)+2*(n)+3*(n-1)+…… +(n+1)*1
=1*n+1 + 2*(n-1)+2 + 3*(n-2)+3 +…… + n*1+n
=1*n+2*(n-1)+3*(n-2)+…… +n*1 + 1+2+...+n
=Sn + 1/2n(n+1)=1/2n²+1/2n
Sn + 1 = (Sn + 1 - Sn) + (Sn - sn-1) +... + (s2-s1) + S1
=1/2(1²+2²+...+n²)+1/2(1+2+...+n)+1
=1/12n(n+1)(2n+1)+1/4n(n+1)+1
So Sn = 1 / 12n (n-1) (2n-1) + 1 / 4N (n-1) + 1 = 1 / 6 (n-1) n (n + 1) + 1 (n ∈ n *)
The use of dashes is: 1) the change of topic; 3) the leap of meaning; 4) the continuation of time or sound dominates the following; 3) the role of ellipsis
For example, "the Himalayas are the highest mountain system in the world on the Asian continent, and Mount Qomolangma is the highest mountain on the earth at present." 2. Progressive: 3. Extended. For example: "Shun Shan Dao" -- the young man of our logging company shouts from the woods
Let F 1, F 2 be the focal point of the ellipse y ^ 2 / 25 + x ^ 2 / 9 = 1, and p be the point on the ellipse
2a+2c=18
The circumference of a quadrilateral is equal to 54 cm. It is known that the first side is equal to a cm, and the second side is 4 cm shorter than the first one
The circumference of a quadrilateral is equal to 54 cm. It is known that the first side is equal to a cm, and the second side is 4 cm shorter than the first,
The length of the third side is 3 cm more than half of the length of the second side. Use a to indicate that the length of the fourth side is
54-A -(A-4) -[(A-4)/2 +3] = 57 - 5A/2
Evaluate (1) sin29 / 6 π (2) cos31 / 4 π (3) Tan (- 1560 °)
Solution
sin(29/6π)
=sin(4π+5π/6)
=sin(5π/6)
=sin(π-π/6)
=sin(π/6)
=1/2
cos(31/4π)
=cos(8π-π/4)
=cos(-π/4)
=cosπ/4
=√2/2
tan(-1560)
=-tan(1560)
=-tan(180×9-60)
=-tan(-60)
=tan(60)
=√3
Given the set a = {m-1,3m, the square of M + 1}, if - 3 belongs to a, find the value of M
When M-1 = - 3, M = - 2, a = {- 3, - 6,5}
2, when 3M = - 3, M = - 1, a = {- 2, - 3,2}
Inverse scale function y = 1-2m / X (M is constant), when X1 / 2, why
For the inverse scale function y = K / X (k is a constant), when k
X divided by 8 equals 15. How do you write the equation
x/8=15
x=15*8
x=120
The concept of function in Senior High School
If f (2x + 1) = x2-2x, then f (3) =?
Let x = 1 in F (2x + 1),
Then, f (2x + 1) = f (2 + 1) = f (3) = 1-2 = - 1