Excuse me, how does cosa Sina = √ 2Sin (a + Wu / 4)?

Excuse me, how does cosa Sina = √ 2Sin (a + Wu / 4)?

cosa-sina
=√2(√2/2cosa-√2/2sina)
=√ 2 (CoS / 4cosa sin / 4sina)
=√ 2cos (a + 4 / 4)
Answer: understand according to four quadrants
If (Sina + COSA) / (Sina COSA) = 3, then 2sin'a + (Sina COSA) '=?
2sin^2a+(sina-cosa)^2=9/5
(sina+cosa)/(sina-cosa)=3
sina+cosa=3(sina-cosa)
tana=2
tan(2a)=2tana/(1-tan^2a)=2*2/(1-4)=-4/3
A in the first or third quadrant
(1) A in the first quadrant
cosa=1/√5,sina=2/√5
2sin^2a+(sina-cosa)^2
=2*(2/√5)^2+(2/√5-1/√5)^2
=9/5
(2) A in the third quadrant
cosa=-1/√5,sina=-2/√5
2sin^2a+(sina-cosa)^2
=2*(-2/√5)^2+(-2/√5+1/√5)^2
=9/5
3x + 2 / 3x = 14
3x + 2 / 3x = 14 multiply by 3
9x+2x=42
11x=42
x=42/11
3x+2/3x=14
11/3x=14
x=14÷11/3
x=42/11
Hope to adopt
If 2x-4y + 5 = 0, what is 3x-6y-5?
2x-4y+5=0
2(x-2y)=-5
x-2y=-5/2
So 3x-6y-5 = 3 (x-2y) - 5 = 3 * (- 5 / 2) - 5 = - 7.5-5 = - 12.5
2x-4y+5=0
2(x-2y)=-5
x-2y=-5/2
So 3x-6y-5 = 3 (x-2y) - 5 = 3 * (- 5 / 2) - 5 = - 7.5-5 = - 12.5
If it helps you, please remember to adopt it_ ∩) O thank you for knowing that the solutions of the equation 4x + 2m = 3x + 1 and the equation 3x + 2m = 6x + 1 about X are the same, so we can find the value of M. ② the algebraic formula (M + 2) to the power of 2011 multiplied by 2m-7 / 5 to the power of 2012 4x + 2m =... Expansion
2x-4y+5=0
2(x-2y)=-5
x-2y=-5/2
So 3x-6y-5 = 3 (x-2y) - 5 = 3 * (- 5 / 2) - 5 = - 7.5-5 = - 12.5
If it helps you, please remember to adopt it_ ∩) O thank you for asking: it is known that the solutions of the equation 4x + 2m = 3x + 1 and the equation 3x + 2m = 6x + 1 about X are the same, so we can find the value of M. ② the algebraic formula (M + 2) to the power of 2011 times the power of 2m-7 / 5 to the power of 2012
14 / 5 + 2 / 3x = 1.2
2/3x=-1.6
x=-2.4
14/5+2/3x=1.2
8/5=-2/3x
x=-12/5..
Given 3x-6y-5 = 0, find the value of 2x-4y + 2008
∵3x-6y-5=0
That is, x-2y = 5 / 3
2x-4y+2008
=2(x-2y)+2008
=2*5/3+2008
=1 / 3 of 2011
3x-6y-5=0
That is, x-2y = 5 / 3
2x-4y+2008=(5/3)*2+2008
3x-6y=5
x-2y=5/3
2x-4y=10/3
2x-4y + 2008 = 2011 1 / 3
Because 3x-6y-5 = 0
So 3x-6y = 5
Multiply both sides by 2 / 3
We get 2x-4y = 10 / 3
Substituting the above formula into 2x-4y + 2008
The original formula is 10 / 3 + 2008 = 6034 / 3
3x-6y-5=0
3x-6y=5
3(x-3y)=5
x-2y=5/3
2x-4y+2008=2(x-2y)
Substituting x-2y = 5 / 3
2x-4y+2008
=（2/3）*（3x-6y-5）+10/3+2008
=6034/3
two thousand and thirteen
Because 3x-6y-5 = 0
So x-2y = 5 / 3
So 2x-4y = 10 / 3
Then we can solve it by substituting it into 2x-4y + 2008.
3 / 5 + 2 / 3x = 14 / 15 (solving equation)
3 / 5 + 2 / 3x = 14 / 15 4 / 7x-1 / 2 = 6 / 7 * 3 / 4 10x + 6x (15-x) = 138 (25% of a number is equal to 20% of 36, what's the number?)
①.X=1/2
②.X=2
③.X=12
④X=28.8
Hope to adopt;
If 3x-6y-5 = 0, then the value of 2x-4y-1 / 3 is 0
3x-6y=5
x-2y=5/3
2x-4y=10/3
2x-4y-1/3=3
The answer is 3
The answer is: 3
The answer is 3!
Solution equation: 3x + 5 / 9 = 14 / 9 (specific point)
3x + 5 / 9 = 14 / 9 (multiply both sides by 9)
27x + 5 = 14
27x = 9 (divide both sides by 27)
X = 1 / 3 (3 * 9 = 27, so 9 / 27 = 1 / 3)
3x+5/9=14/9
3x=14/9-5/9
3x=1
x=1/3
3x+5/9=14/9
3x=14/9-5/9
3x=1
So x = 1 / 3
3x=14/9-5/9
3x=3
X=1
Remove the denominator to get 27x + 5 = 14, shift the term to get 27x = 9, and change the coefficient to 1 to get x = 1 / 3
Given 3x-6y = 0, find the value of 2x-4y + 6
3x-6y=0
x-2y=0
2x-4y+6
=2(x-2y)+6
=0+6
=6
3x-6y=0
3(x-2y)=0
x-2y=0
2x-4y+6=2(x-2y)+6=0+6=6
If it helps you, please remember to adopt it_ Thank you
3x-6y=0
So 3 (x-2y) = 0
So x-2y = 0
2x-4y+6=2（x-2y）+6=2x0+6=6
I wish you progress in your study. Thank you... Question: given that the root of the equation 3x + a = 0 about X is 2 larger than that of the equation 5x-a = 0 about X, then the value of a is (?)