What degrees of angle can you get by folding a piece of circular paper three times and unfolding it? Please write three words:___ 、___ 、___ ．

What degrees of angle can you get by folding a piece of circular paper three times and unfolding it? Please write three words:___ 、___ 、___ ．

According to the analysis, a piece of circular paper is folded in half for three times and then unfolded. The number of angles can be obtained: 180 °, 90 ° and 45 °. So the answer is: 180 °, 90 ° and 45 °

A simple trigonometric function of acute angle!
In the acute triangle ABC, ab = 15, BC = 14, s triangle ABC = 84, find: ① tangent of angle c; ② sine of angle A

If a right triangle is constructed, CD is perpendicular to ab through point C, and ad is x, then BD = 15-x
CD=sin84*14≈13.9
In RT triangle BCD, CD ^ + BD ^ = BC^
That is to say, 13.9 ^ + (15-x) ^ = 14 ^ gives X=
So Tanc = ad: CD = x: 13.9
Sina = CD: AC = 13.9: radical (x ^ + 13.9 ^)

Calculating trigonometric function of acute angle
(1) Sin ^ 2 30 degree + cos ^ 2 30 degree=____ +_____ =_____
(2) Sin ^ 2 45 degrees + cos ^ 2 45 degrees=_____ +_____ =_____
(3) Sin ^ 2 60 degrees + cos ^ 2 60 degrees=_____ +____ =___
Conjecture: when angle a is an acute angle, sin ^ 2A + cos ^ 2A=_____

(1) Sin ^ 2 30 degree + cos ^ 2 30 degree=____ +_____ =_____ (2) Sin ^ 2 45 degrees + cos ^ 2 45 degrees=_____ +_____ =_____ (3) Sin ^ 2 60 degrees + cos ^ 2 60 degrees=_____ +____ =___ Conjecture: when angle a is an acute angle, sin ^ 2A + cos ^ 2A=_____ Is sin ^ 2 30 a bungalow with sin 30

Several on the calculation of acute trigonometric function, help 58!
I lost my calculator, so please help me with it
Cos76 degrees 39 points =? Cos4 degrees 59 points =?
Sin17 degrees 52 points =? Sin57 degrees 18 points =? Sin15 degrees =?
Tan 22 degrees 30 minutes =? Tan 83 degrees 6 minutes =? Tan 12 degrees 30 minutes =?

Cos76 degrees 39 points =? 0.23089
Cos4 degree 59 =? 0.99622
Sin17 degrees 52 points =? 0.3068
Sin57 degrees 18 points =? 0.8415
Sin15 degrees =? 0.2588
Tan 22 degrees 30 minutes =? 0.41421
Tan83 degrees 6 points =? 8.26355
Tan 12 degrees 30 minutes =? 0.22169

Acute trigonometric function: how to calculate the angle?

Acute angle trigonometric function, generally can put the required angle in the right triangle to study
Let △ ABC be a right triangle and ∠ C = 90 °, then:
sinA=BC/AB
cosA=AC/AB
tanA=BC/AC

An acute angle trigonometric function problem in the third grade of junior high school mathematics,
In the triangle ABC, angle c = 90, angle a, angle B, and the opposite sides of angle c are a, B, and C. if the perimeter of triangle ABC is 30 and the area is 30, find a, B, and C

A B C = 30
a^2 b^2=c^2
1/2*ab=30
From the above three formulas, C = 13
A = 5, B = 12 or a = 12, B = 5

As shown in the figure, in the parallelogram ABCD, AE ⊥ BC is in E, AF ⊥ CD is in F, ∠ EAF = 45 ° and AE + AF = 22, then the perimeter of the parallelogram ABCD is______ ．

In RT △ Abe, according to Pythagorean theorem, we can get AB = 2x and ad = 2 (22-x), then the perimeter of parallelogram ABCD is 2 (AB + AD) = 2 [2x + 2 (22-x)] = 8

A professional fish farmer contracted a fish pond and put in 100000 fry. According to the scientific calculation and fish culture experience, we know that the survival rate of fish is about 90%. After a period of time, in order to understand the growth of fish and scientifically master the feeding density, we need to know the total weight of fish in the pond. For the first time, 36 fish were netted and weighed 73kg; for the second time, 52 fish were netted and weighed 117kg; for the third time, 32 fish were netted, The average weight is 2.5kg. Please estimate the total weight of fish in the pond according to the above information?

A total of 36 + 52 + 32 = 120
Total weight 73 + 117 + 32 × 2.5 = 270 kg
Average 270 △ 120 = 2.25 kg
The survival rate was 90%
10×90%×2.25=20.25
A: it is estimated that the total weight of fish in the pond is 202500 kg

If a > 1, what about the roots of the quadratic equation 2 (a + 1) x2 + 4ax + 2a-1 = 0?
Solving equation (Y-1) (y + 3) = 5
2 (x-1) 2-5 (x-1) + 2 = 0 is the square of (x-1)

A discussion on the roots of quadratic equation of one variable: B & sup2; - 4ac = 16A & sup2; - 8 (a + 1) (2a-1) = 8-8a, since a is greater than 1, then 8-8a is less than zero, then the equation has no real roots. Solve equation 1, Y & sup2; + 3y-y-3 = 5Y & sup2; + 2y-8 = 0 (y + 4) (Y-2) = 0y = - 4 or y = 22, 2x & sup2; - 4x + 2-5x + 5 + 2 = 02x & sup2; -

After executing the statement "x = (a = 3, B = a --", the values of X, a and B are

Perform a = 3 first
Then execute B = a --, B = 3
Then a -- takes effect, a = 2
(a = 3, B = a --) returns the last expression B of the comma
That is, x = b = 3
So a = 2, B = 3, x = 3