If you come across a quadratic trigonometric equation........hmmmm

Quadratic trigonometric equations are just like any other quadratic fequations. Dont see sinx / cosx / tanx as a BIG thing...if you look carefully, replace the trigonometric identities with a simple x, you will see the nostalgicity of it ; it will look like a regular quadratic equation.

there are generally 4 methods you can use to solve a quadratic trigonometric equation. stay calm and look carefully =)

method 1. common factor (factor out the common trigonometric identity and equate them to zero to find the acute angle,x)

method 2. trinomial factor (factorise the whole equation to get something like (kx + a)(jx + b). equate each polynomial to zero to find the acute angle, x)

method 3. replace 'complex' trigonometric identities with simpler ones (using the trigonometric formulas. then factor them, and again, equate it to zero to find the acute angle, x)

method 4. quadratic formula (use the quadratic formula to determine the roots of an unfactorable trigonometric equation. or simply use the GC)

Sorry to be repetitive, but seriously, it's nothing much of a big deal. Take it as a quadratic equation you are required to solve.

For example,

tanxcos²x = tanx    (uh-ohhhhhhh...what now?!)

Remember the identity cos²x = 1 – sin²x  ? Use it!

Substitute it into the equation and you will get tanx (cos²x – 1)Factor out (cos²x – 1) so you can find the acute angle of x.
See...Told you it isnt THAT tough   =D