In this tutorial we give you a practice question on proving trig identities. The question is: Prove that (1-sinx)/(1+sinx)=(secx-tanx)^2. Have a go then come and see the answer! p.s. Need to remember how to factorise and expand binomials 🙂
In this tutorial we give you a practice question on proving trig identities. The question is: Prove that (cot^2(x)-1)/(cot^2(x)+1) = 1-2sin^2(x). Have a go then come and see the answer!
In this tutorial we talk about some more Trig identity proofs, including: tan(x) = sin(x) / cos(x) sin^2(x) + cos^2(x) = 1 tan^2(x) + 1 = sec^2(x) cot^2(x) + 1 = cosec^2(x)
In this series of videos I will prove every single trigonometric identity. If you have any that you want to see the proof of, feel free to e-mail me. I suggest starting from the beginning so if you are stuck watching this video, go back to some earlier ones (e.g. the proof of sin(A+B))
In this video I present this proof in the smallest steps possible. All you need to know to understand this are the basic trig rules sin(theta)=opposite/hypotenuse etc.
In this lesson we solve more trigonometric equations, this time using exact values (without a calculator). Must be good with fractions to do this!
In this tutorial we start talking about solving trigonometric equations such as sin(x)=0.5 where x can have multiple answers depending on its domain.
In this lesson we use a combination of techniques that you have learned in previous lessons to find the exact values of trigonometric ratios for angles larger than 90 degrees.
We talk about how to find the values of sin, cos and tan in quadrants 2, 3 or 4, given the value of sin, cos or tan in the first quadrant. e.g. sin(150 degrees)=sin(30 degrees).
In this lesson you learn how to express trigonometric ratios as exact values. For example, instead of typing cos30 in the calculator to get 0.866, after doing this tutorial you will be able to write cos30 = sqrt(3)/2 without using the calculator.