Sina to cosa

Sina to cosa

sin²A＋cos²A=1
sinA=cos(π/2－A)
sinA=cos(3π/2＋A)

If Sina + cosa / Sina cosa = 2, then the value of sinacosa is?

(sina+cosa)/(sina-cosa)=2
sina+cosa=2sina-2cosa
sina=3cosa
Let Sina = 3k, cosa = K
So (3K) ² + K & #178; = 1
k²=1/10
sinacosa=3k²=3/10

Sina * cosa = 1 / 2, 2sina * cosa = 1, sin2a = 1, 2A = 90 or 450, a = 45 degrees or a = 225 degrees

Draw an image of sine function, a = 45 ° 2A = 90 ° so it holds

Sina + cosa = 4 / 5 find sin2a =?

(sina+cosa)^2=1+Sin2a=16/25 sin2a=-9/25

sin2a=1/4,sina-cosa=?

sin2a =2siacosa=1/4
(sina - cosa)^2 = (sina)^2 - 2sinacosa + (cosa)^2 = (sina)^2 + (cosa)^2 - 2sinacosa
=1 - 1/4
=3/4
sina - cosa = ±√3/2

Prove [Sina (1 + Sina) + cos (1 + COSA)] [Sina (1-sina) + cos (1-cosa)] = sin2a

Prove: left = (Sina + Sin & # 178; a + cosa + cos & # 178; a) (Sina Sin & # 178; a + cosa cos & # 178; a) = (Sina + cosa + 1) (Sina + cosa-1) = (Sina + COSA) &# 178; - 1 = Sin & # 178; a + 2sinacosa + cos & # 178; A-1 = 2sinacosa = sin2a = right

A value of a whose distance from point a (COS 2a, sin2a) to point B (COSA, Sina) is 1 is
The answer is - TT / 3 fast

(cos2a-cosa)^2+(sin2a-sina)^2=1 (cos2a)^2+(sin2a)^2+(sina)^2+(cosa)^2-2cos2acosa-2sin2asina=12-2cos2acosa-2sin2asina=12cos2acosa+2sin2asina=1cos(2a-a)=1/2cosa=1/2a=2kπ±π/3

If Sina + cosa = 1 / 3, then cos2a=

From: Sina + cosa = 1 / 3, (Sina + COSA) ^ 2 = (1 / 3) ^ 2 (Sina) ^ 2 + 2sinacosa + (COSA) ^ 2 = 1 / 91 + 2sinacosa = 1 / 9sin2a = - 8 / 9, because: (sin2a) ^ 2 + (cos2a) ^ 2 = 1, so: cos2a = ± √ [1 - (- 8 / 9) ^ 2] = ± √ (17 / 81) = ± √ 17 / 9

Given the two-point coordinates P (COSA, Sina). Q (2 + Sina, 2 + COSA), a ∈ [0, π], then the range of | vector PQ | is
Can you be more specific?? Thank you~~

PQ = (2 + Sina cosa, 2 + cosa Sina) = (2,2) + √ 2 (sin (a-45 °), cos (a + 45 °) = (2,2) + √ 2 (sin (a-45 °), - sin (a-45 °)). It can be seen that if P is placed at the origin, Q will fall above x + y = 4, between (3,1) and (1,3)

If the terminal edge of angle a passes through (2a-3,4-a), Cosa ≤ 0 and Sina > 0, then the value range of real number a is ()
If the terminal edge of angle a passes through (2a-3,4-a), Cosa ≤ 0 and Sina > 0, then the value range of real number a is ()

Answer:
The final edge of angle a is known to pass through (2a-3,4-a), Cosa ≤ 0, Sina > 0,
The final edge of angle a is in the second quadrant or the nonnegative half axis of y-axis,
∴ 2a-3≤0,4-a>0
A ≤ 3 / 2 and a