All equations are solved using inverse functions. That is, we “undo” operations on a variable to ultimately find the value of that variable.
For example, When we solve 2x + 3 = 15, we first subtract 3 from both sides of the equation. This is because -3 is the inverse operation to +3, and this allows us to remove the + 3 from the left hand side of the equation. We now have 2x = 12. Now, notice that 2x means that x has been multiplied by two. The inverse operation to multiplying by two is dividing by two (÷2 or /2), so we divide both sides of the equation by two and obtain our “solution,” x = 6!
In a similar way, when we need to solve sin(x) = 0.5, for example, we need some function or operation to “remove the sine function from the x” on the left hand side of the equation. Mathematicians devised such a function and called it the “inverse sine” function. It can be written sin‾¹ (or arcsin in the USA) and is called “the inverse sine” function. Therefore, our solution should look similar to that in the image above.
There are more “tricks to the trade” as the complexity of equations increases, but the priciple that I have shown you here underlies them all.
One of my YouTube subscribers presented me with two trigonometric equations to solve. This is the first of them:
tany - 2 = coty, where 0° ≤ y ≤ 180°
If you watch this video you should discover:
key things to look for in such an equation,
how to resolve it into a quadratic equation,
how to check the nature of the roots/zeros
how to find the roots/zeros,
how to use the unit circle to find the relevant angles, and
how to identify the angles within the restricted domain.
The video is a little longer than it might have been because I explain each step without skipping over too many details. If you have difficulty solving equations of this type you should learn some useful skills here.
This is the second of two trigonometric equations that one of my YouTube subscribers asked me to solve.
The equation in question is:
2.sin(x + π/3) = -1, where 0 ≤ x ≤ 2π
If you watch this video, you should discover:
key things to look for in such an equation,
how to simplify the equation,
how to use triangles and the unit circle to identify angles, and
how to identify the angles within the restricted domain.
We were all deeply impressed with Graeme from the very beginning. [Lucas’] confidence radically changed within only 3 weeks of Graeme’s instruction and assistance. I am sure this was largely attributed to Graeme’s infectious passion and love for his subject, and his high personal level of skill, teaching experience and understanding of mathematics. Lucas always found Graeme could explain concepts so knowledgeably and easily, which really did transform Lucas’ appreciation and enjoyment of the subject. Graeme always gave Lucas assistance and time over and above his hour’s tutoring session. Graeme has developed a wonderful relationship and more of a mentoring role which has been of great assistance and value to Lucas as he faces the pressures of his final year of school. I have no hesitation in recommending Graeme as an outstanding tutor and friend, and a very wise, knowledgeable and capable teacher of the highest calibre.
Sally T (parent, 2005)
