Maths Help (1 Viewer)

[Farhanthestudent005]

√3sinx = cosx

How do I solve this equation?I know it may seem easy but I forgot. Please help me thank you

 

[idkkdi]

√3sinx = cosx

How do I solve this equation?I know it may seem easy but I forgot. Please help me thank you

divide by sinx or cosx

 

[Trebla]

Moved to Maths Ext1 thread.

For future reference, please post these questions in the Maths forum.

 

[pikachu975]

√3sinx = cosx

How do I solve this equation?I know it may seem easy but I forgot. Please help me thank you

Minus cosx to both sides, so sqrt3 sinx - cosx = 0
cosx (sqrt3 tanx - 1) = 0
cosx = 0 and tanx = 1/sqrt3
cosx = 0 isn't valid since tan(pi/2) doesn't exist so only tanx = 1/sqrt3 is a solution
x = pi/6 then the other solutions depend on the domain of x

In this case dividing by cosx on both sides would give the right answer but in other questions it might remove a solution so be careful

 

[viennamotley]

I'd say the question wants you to use auxiliary angles

 

[idkkdi]

Minus cosx to both sides, so sqrt3 sinx - cosx = 0
cosx (sqrt3 tanx - 1) = 0
cosx = 0 and tanx = 1/sqrt3
cosx = 0 isn't valid since tan(pi/2) doesn't exist so only tanx = 1/sqrt3 is a solution
x = pi/6 then the other solutions depend on the domain of x

In this case dividing by cosx on both sides would give the right answer but in other questions it might remove a solution so be careful

ye check scenario where the thing u divide by = 0 , in case that is a possible solution.

 

[idkkdi]

I'd say the question wants you to use auxiliary angles

probably lol.