/sci/ - Science & Math

[Anonymous No.10694551]

Some big brain do this pls
2sinx*cosx=0

[Anonymous No.10694557]

[math] \forall n\in\mathbb{W}\qquad x=n\pi/2 [/math]

[Anonymous No.10694558]

>>10694551
x=n*pi/2 where n is any integer

[Anonymous No.10694567]

>>10694558
>>10694557
is there any more steps than just the last? Im doing this on test

[Anonymous No.10694576]

>>10694567
What steps...? the inverse of the function f(x)=2sinx*cosx cannot be written down in closed form. Literally just graph that bitch and look at where the zeros are. Or, plug in n*pi/2 and notice it is a zero for any integer n.
t. engineer

[Anonymous No.10694582]

>>10694576
addendum:
im pretty retarded btw. you could also just use trig identities to prove that f(x)=2sinxcosx=sin(x/2)
sin(x/2)=0 => arcsin(0)=x/2
for which the principle zero of f is 0

[Anonymous No.10694585]

>>10694551
2*sin(x)*cos(x) = sin(2x)
sin(2x)=0

Pretty easy from there. If you don't have the trigonometric identities for sine and cosine memorized (sums and differences in the arguments, and double angles at the minimum), you're not gonna make it.

[Anonymous No.10694593]

>>10694551
You got summer school lad?

[Anonymous No.10694595]

>>10694576
thank you sorry for doing retard talk for me

[Anonymous No.10694600]

>>10694593
doing this for even more retarded brother who is pic rel fatty

[Anonymous No.10694633]

>>10694551
https://www.google.com/search?q=y%3D2*sin%28x%29+*cos+%28x%29

[Anonymous No.10694704]

Holly shit why retards use trig identities when a product is obviously equall to zero when one of it's factor is zero. This way you can teach toddlers to solve this shitty problem. Maybe op did not started to learn trig identities.

[Anonymous No.10694714]

>>10694704
>implying there's any difference between the two representations

[Anonymous No.10694758]

>>10694582
I believe you mean 2sin(x)cos(x) = sin(2x)
sin(2x) = 0
sine is the height of a reference triangle at a given angle on the unit circle. Therefore, it is 0 at 0 and pi, and all multiples of pi.
In other words, 2x = n*pi where n is an integer
x = n*pi/2

[Anonymous No.10694764]

2sinx*cosx = 0
sinx = 0 or cosx = 0

x = n*pi or x = n*pi/2
since n*pi = 2*n*pi/2
x = n * pi/2, n is part of Z

[Anonymous No.10694957]

>>10694551
Zero property: multiplying any number by zero always yields a product of zero.

So, split the equation. Where does sinx = 0, and where does cosx = 0?

[Anonymous No.10695033]

>>10694585
>...sine and cosine memorized

he actually memorized the identities instead of deriving them

[Anonymous No.10695181]

>>10695033
>he doesnt memorize mundane mathematical properties
You aren't going to get far