How to deduce that sin (π / 2-A) = cosa, cos (π / 2-A) = Sina? A is alpha How to deduce from the induction formula sin(π/2-a)=cosa, cos(π/2-a)=sina A is alpha I'm confused about math I can remember the formula, but learning can't just stay at the level of knowing it

How to deduce that sin (π / 2-A) = cosa, cos (π / 2-A) = Sina? A is alpha How to deduce from the induction formula sin(π/2-a)=cosa, cos(π/2-a)=sina A is alpha I'm confused about math I can remember the formula, but learning can't just stay at the level of knowing it

sin(π/2-a)=sin(π/2)*cosa-cos(π/2)*sina
Because sin (π / 2) = 1, cos (π / 2) = 0
So sin (π / 2-A) = 1 * cosa-0 * Sina = cosa
cos(π/2-a)=cos(π/2)*cosa+sin(π/2)*sina=0*cosa+1*sina=sina

The induction formula sin (a + b) =, sin (a + b) / 2, cos (a + b) =, cos (a + b) / 2, Tan (a + b), Tan (a + b) / 2

A+B+C=π,A+B=π-C,(A+B)/2=(π-C)/2=π/2-C/2,sin(A+B)=sin(π-C)=sinC,sin[(A+B)/2]=sin(π/2-C/2)=cos(C/2),cos(A+B)=cos(π-C)=-cosC,cos[(A+B)/2]=cos(π/2-C/2)=sin(C/2),tan(A+B)=tan(π-C)=-tanC,tan[(A+B)/...

A problem solved by induction formula if Tan (Π - α) = 2, find the value of 2Sin (3 Π + α) × cos (5 Π / 2 + α) + sin (3 Π / 2 - α) × sin (Π - α)

tan(∏-α)=2
-tanα=2
sinα/cosα=tanα=-2
sinα=-2cosα
Substituting the identity sin 2 α + cos 2 α = 1
Then cos 2 α = 1 / 5
sin²α=4/5
sinαcosα=(-2cosα)cosα=-2cos²α=-2/5
The original formula = - 2Sin α (- sin α) + (- cos α) sin α)
=2sin²α-sinαcosα
=2

How to change sin (3 π / 2 - a) with induction formula 3 π / 2 is a whole

sin(3π/2-α)
=sin(3π/2-α-2π)
=sin(-π/2-α)
=-sin(π/2+α)
=-sin[π/2-(-α)]
=-cos(-α)
=-cosα

The induction formula sin (3 π / 2 + α) =?, cos (3 π / 2 + α) =?, Tan (3 π / 2 + α) =? Please refer to the supplementary question for details, 1、sin(3π/2+α)=? 2、cos(3π/2+α)=? 3、tan(3π/2+α)=? 4、sin(3π/2-α)=? 5、cos(3π/2-α)=? 6、tan(3π/2-α)=? 7. What is odd change even invariance, symbol look quadrant?

1、cosα
2、-sinα
3、-tanα
4、-cosα
5、-sinα
6、tanα
7. N π / 2 when n is an odd number, sin changes into cos, cos changes into sin; then take α as an acute angle to see which quadrant the original angle is in, and then change the sign according to the positive and negative values of different quadrants

The sine function sin a represents

Trigonometric function is a kind of transcendental function which belongs to elementary function in mathematics. Its essence is the mapping between the set of arbitrary angles and the variables of a ratio set. The usual trigonometric function is defined in the plane rectangular coordinate system, and its definition domain is the whole real number field. Another definition is in the right triangle, In modern mathematics, they are described as the limit of infinite sequence and the solution of differential equation, and their definition is extended to complex system. Sine function sin θ = Y / R sine function sin (a) = A / C
sin0=0

The function value sin (- 1305 °) can be calculated by the induction formula

sin(-1305°)
=sin(-1305°+360°*4)
=sin135°
=√2/2

What symmetry is the image of the sine function y = sin = x about

y＝sinx
With symmetric center (K π, 0)
Axis of symmetry x = k π + π / 2
It is symmetrical about the axis and center of symmetry

How many degrees of sin is equal to 0.94? It is better to provide a sine function value table

The closest is sin (70 degrees 3 points) = 0.93999
You can buy a math manual in the library. There are all kinds of tables in it

What is the Laplace transform of sine function sin

w^2/s^2+w^2