sin x + cos x = 0 (1 Viewer)

[sampson9002]

for what value of x will sin x + cos x = 0 between 0 and 2pi?

also i need working as to how you would show this in an exam

 

[Bacchus]

for what value of x will sin x + cos x = 0?

also i need working as to how you would show this in an exam

Rsin(x+@) = Rsinxcos@+Rcosxsin@ = sinx + cosx

Rcos@ = 1 and Rsin@ = 1
tan@ = 1
@ = pi/4
R = sqrt(2)

so sinx + cosx = sqrt(2) sin(x+pi/4) = 0
sin(x+pi/4) = 0
x +pi/4 = (-1)^n 0 + 2kpi
x = 2kpi - pi/4 (since you didn't provide any domain)

 

[sampson9002]

Rsin(x+@) = Rsinxcos@+Rcosxsin@ = sinx + cosx

is that a 3 unit rule? cause im only doin 2unit and this question is out of a 2 unit book

 

[iSplicer]

Rsin(x+@) = Rsinxcos@+Rcosxsin@ = sinx + cosx

is that a 3 unit rule? cause im only doin 2unit and this question is out of a 2 unit book

Yes, he is using transformation which is 3 unit.

for two unit, just divide everything by cos x, which will give you tan x + 1 = 0, then just solve that =D

 

[sampson9002]

righto thanks mate

 

[Drongoski]

All you need here is:

T/4: sin x + cos x = 0

T/4: sin x = - cos x

T/4: tan x = - 1

x = 135 and 225 degrees

 

[muz01]

lol i didnt no u were on here sampson bro

 

[iSplicer]

righto thanks mate

No problem