An acute angle trigonometric function in the third grade of junior high school cos48°+cos40°/sin50°-sin42°

An acute angle trigonometric function in the third grade of junior high school cos48°+cos40°/sin50°-sin42°

cos48°+cos40°/sin50°-sin42°
=sin42°+sin50°/sin50°-sin42°
=0+1
=1
Cos 48 ° is sin42 ° and COS 40 ° is sin50 ° so
The original formula is 1
One
It is known that f (x) is an even function on R, satisfying f (x) = - f (x + 1). When x ∈ [20112012], f (x) = x-2003, then ()
A.f(sinπ/3)＞f(cosπ/3)
B.f(sin2)＞f(cos2)
C.f(sinπ/5)＜f(cosπ/5)
D.f(sin1)＜f(cos1)
Satisfy f (x) = - f (x + 1), f (x + 1) = - f (x + 2), so f (x) = f (x + 2), so the period T of F (x) is 2. When x ∈ [20112012], the image shape is the same as that when x ∈ [- 1,0], but the left and right positions are different. When x ∈ [20112012], f (x) = x-2003, which is an increasing function, so f (x) on X ∈ [- 1,0] is
The answer is C
∵f(X)=-f(x+1)
∴f(x+2)=-f(x+1)=f(x)
If f (x) is a periodic function, the period T = 2
When ∵ x ∈ [20112012], f (x) = x-2003
Let x ∈ [0,1]; - x ∈ [- 1,0]
∴2012-x∈[2011,2012]
∴f(x)=f(-x)=f(2012-x)=2012-x-2013=-1-x
sinπ/3>cosπ/3>0
∴.f(sinπ/3)0
∴sin(π-2)>sin(2-π/2)
F [sin (π - 2)]
What problem can be solved with acute trigonometric function
For example, Sina = 3 / 4, what conditions can be obtained?
How to understand this theorem?
What kind of problems do you use it to solve?
What is the general idea of solving the problem?
1. If Sina = 3 / 4, the cosine can be 7 / 4, and other trigonometric functions can also be obtained,
2. Understanding is that the opposite side of a right triangle is larger than the hypotenuse,
Trigonometric function, geometry, integral, application==
4. It's natural to be long
Most of them are used to solve three sides and three angles of a triangle
Use Sina = 3 / 4 to find the angle of this angle and the ratio of their sides.. wait
If a period of the periodic function f (x) defined on R is 5, then f (2011) is 5?
Because the period of function f (3x + 1) is 3, the period of function f (x) is 3 × 3 = 9. It is known that the function f (x) defined on R is odd, and the period of function f (3x 1) is 3, if f (1)
F (2011) = f (1)
The problem of acute angle trigonometric function (2),
1. In △ ABC, ∠ C = 90 °, ab = 4, BC = 2, then Sina = (), cosa = (), Tana = (), SINB = (), CoSb = (), tanb = ()
2. In △ ABC, ∠ C = 90 ° and ab = 2Ac, then Sina = (), cosa = (), Tana = (), SINB = (), CoSb = (), tanb = ()
3. In △ ABC, ∠ C = 90 ° and ∠ B = 2 ∠ a, then Sina = (), cosa = (), Tana = (), SINB = (), CoSb = (), tanb = ()
1. 1 / 2, 2 / 2, 3 / 3, 2 / 2, 3 / 3
2. 2 / 2, 3; 1 / 2, 2 / 3, 3 / 3
3. Same question
FX = √ 3sinx cosx, X ∈ (Wu / 2, Wu), find the minimum value of the function and the corresponding value of X
FX = 2Sin (x-wu / 6); when x = Wu, the minimum value is obtained, and the minimum value is 1
An acute angle trigonometric function problem in the third grade of junior high school
sin2 31°+tan2 31°*tan2 59°+sin2 59°
That two is square
sin2 31°+tan2 31°*tan2 59°+sin2 59°
=sin2 31°+1+sin2 59
=2
sin59=cos31
cos59=sin31
tan31=sin31/cos31
tan59=sin31/cos31
Just insert all of them
The function f (x) = (SiNx + cosx) ^ 2 + 2cos ^ 2x-2 is known. Find the monotone increasing interval of (1) f (x). (2) when x belongs to [Wu / 4,3 Wu /...]
The function f (x) = (SiNx + cosx) ^ 2 + 2cos ^ 2x-2 is known. Find the monotone increasing interval of (1) f (x). (2) when x belongs to [Wu / 4,3 Wu / 4], find the maximum and minimum of function f (x)
f'(x)=1+2sinxcosx+cos2x-1=√2sin(2x+π/4)
1) The monotone increasing interval is 2K π - π / 2=
How to make a circle at a 45 degree angle
Fold in half, fold in half, fold in half, and then fold in half
-The square of 3 + 5x (- 8) - (- 2) to the third power
9-40-2=-33