First grade mathematics degree minute second calculation problem 48°39'+67°41'= -78°19'40''=

First grade mathematics degree minute second calculation problem 48°39'+67°41'= -78°19'40''=

48 ° 39 '+ 67 ° 41' = 48 ° + 67 ° + (39 / 60 + 41 / 60) ° = 116 ° 20 '- 78 ° 19'40' '= - {78 ° + (19 / 60) ° + (40 / 3600) °} = 78.328 ° degrees, minutes and seconds are carried by 60, minutes divided by 60 are converted into degrees, seconds divided by 60 are converted into minutes, seconds are directly converted into degrees divided by 60 * 60

The conversion of degree, minute and second
one hundred and twenty-three

The decimal system of degree, minute and second is 60, which is divided by 60 when converted to decimal. For example, 10 "conversion component is divided by 60, which is divided by 3600 when converted to degree. Similarly, 15" conversion component is also divided by 60.1 degree = 60 minutes and 1 minute = 60 seconds
1 degree = 3600 seconds
Take your time

A few questions about mathematics in grade one of junior high school
We must write the process
30°34′＋21°41′=
180°-53°31′=
90 ° to 7 (accurate to 1)
26°17′45〃×3-42°21′11〃=

30°34′+21°41′=（30°+21°）+（34′+41′）=51°75′=52°15′180°-53°31′=179°60′-53°31′=126°29′90°÷7≈13°26°17′45〃×3-42°21′11〃=78°51′135〃-42°21′11〃=36°30′124〃=36°32′04...

The sum of number a and number B is 2009. The number a is divided by the number B quotient of 333, and the number a is () and the number B is ()
Please give me some advice. I'm really in a hurry. Please

A is x, B is 2009-x
（2009-x）*333+5=x
2009*333-333x+5=x
334x=669002
x=2003
The number B is six

It is known that the side area of a cone is twice of the bottom area, and the degree of the center angle of the cone's side expansion is calculated

The formulas that need to be used are
Sector area: S = n π a ^ 2 / 360
Circle area: S = π R ^ 2
Cone side area: S = π RA (n is the center angle, a is the generatrix)
Because the side area of the cone is twice the area of the bottom circle
So π RA = 2 π R ^ 2
a=2r
And because the sector area of the side of the cone is twice the area of the bottom circle
So n π a ^ 2 / 360 = 2 π R ^ 2
That is n π (2R) ^ 2 / 360 = 2 π R ^ 2
4nπr^2/360=2πr^2
n=2πr^2/(4πr^2/360)
n=180
So the degree of the center angle of the cone side expansion is 180 degrees

Matlab to solve the equation. How can we not solve the solution ('x + 1319.2 * exp (- 3.973 * log (5.15 * (10 ^ 18) / X / x)) - 1484.13 = 0 ')

Your equation seems to be written wrong
first,
5.15*（10^18）
It can write 5.15e18 directly,
Secondly, / X / x, isn't it possible to make an appointment?
It's changed to this: solve ('x + 1319.2 * exp (- 3.973 * log (5.15e18)) - 1484.13 = 0 ')
Results of operation:
ans =
one thousand four hundred and eighty-four point one three
>>

(1) For any real number a, B, prove a ^ 2 + 3B ^ 2 ≥ 2B (a + b)
(2) For any real number AB, prove a ^ 2 + B ^ 2-2a-2 ≥ 0
(3) Given ABC positive integers, proving (with mean value theorem)
a(b^2+c^2)+b(c^2+a^2)+c(a^2+b^2)≥6abc
（a^2+1）(b^2+1)(c^2+1)≥8abc

Third grade math problem: find the perimeter and area of the figure below

The first perimeter is 8 + 4 + 12 + 12 + 4 = 40 cm
The area is 4 × 12 + 4 × 4 = 48 + 16 = 64 cm and 178 cm;
The second perimeter is 20 + 30 + 30 + 8 + 12 + 20 = 50 + 38 + 32 = 88 + 32 = 120 decimeters
Area: 20 × 30-8 × 12 = 600-96 = 504 square decimeters

If in the quadrilateral ABCD, the degree of ∠ A: B: C: D = 1:2:4:5

Let angle a, angle B, angle c and angle d be x, 2x, 4x and 5x respectively
Because the sum of the internal angles of a quadrilateral is 360 degrees
So, x + 2x + 4x + 5x = 360
12X=360
X=30
So, angle a = x = 30 degrees
Angle d = 5x = 5 times 30 = 150 degrees
If you don't understand, you are welcome to ask,

Write out two polynomials which only contain the letters X and y, and satisfy the following conditions: (1) 6 times trinomial equation (2) the coefficient of each term is 1 or - 1. (3) there is no constant term. (4) each term must contain the letters X and y at the same time

X ^ 3 * y ^ 3 + x ^ 2 * y ^ 4 + X * y ^ 56 times trinomial, that is, the highest degree is 6. For example, the third power of X multiplied by the third power of Y, this term is the monomial with the degree of 6 (it is not easy to understand the sign). That is to say, the above three formulas are all three terms with the degree of 6, which only contains the multiplication sign, and the addition or subtraction formula is the monomial, such as XY, x ^