Hello students. If you are in Class 10 under SEBA or CBSE board, you must be having doubts in trigonometry. Trigonometry seems to be one of the scariest topic in your mathematics syllabus.
That’s why in the latest live class of our official Youtube channel – EduAid Classroom, Prakitesh Sir has tried you address this issue for you. In this class sir has put stress on observation skill – a skill that helps students solve mathematical problems. Sir has introduced this goldmine skill by solving some numericals of the trigonometry exercise. If you want to watch the video check below :
Table of Contents
In this article, we are trying to give you a gist/summary of the live class taken by Prakitesh Sir. Here’s the breakdown of how to master trigonometry like a pro.
The MCQ "Cheat Code": Angle Assumption
When you’re facing those multiple-choice questions (MCQs), you don’t always have to solve them the long way. Prakritesh Sir mentioned four main ways to tackle them:
a) the theoretical approach,
b) Use of options,
and the most efficient one—
c) the logical assumption approach.
Instead of doing massive algebraic shifts, just assume a value for the angle ( ). For example, for many problems in Exercise 8.4, you can substitute = 45∘. Since tan 45∘ = 1 and cot 45∘= 1, the math becomes incredibly simple, and you can find your answer in seconds.
The "No-Infinity" Rule
There is one big catch to the shortcut above: you have to be careful which angle you choose. You must avoid any angle that makes the trigonometric function undefined or “infinity.”
- Don’t use 90∘if you see “tan” or “sec” in the problem.
- Don’t use 0∘ if there is a “cot” or “cosec”.
- Pro Tip: Stick to 30∘, 45∘, or 60∘ to stay safe and get a clear result.
Cracking Long Proofs: Look at the RHS!
For the subjective questions where you have to “prove that LHS = RHS,” students often get lost in the middle of the math. Sir’s advice? Let the Right-Hand Side (RHS) be your GPS.
Before you even start writing, interpret what the RHS is telling you. If the RHS has sec A and tan A, you know you need to work toward getting a cos A in the denominator of your fractions. Whether you are multiplying by a conjugate (like 1 + sin A) or dividing the numerator and denominator by a specific term, every step should be a move toward matching that RHS.
Don’t Lose the "Easy" 45 Marks
While shortcuts are great for MCQs, the remaining 45 marks of your paper depend on how you present your work. Prakritesh Sir emphasized that presentation is essential. An examiner can judge a student based on its presentation skill i.e. answer writing skill. You need to write clear, logical steps and state what you are proving to leave a good impression on the examiner. Even if you know the answer, messy work can cost you dearly.
Final Thoughts
Mathematics is more about observation than just memorizing formulas. If you focus on your NCERT book and practice looking at where the question is trying to go, you’ll find that trigonometry isn’t a mountain—it’s just a series of small steps.
Analogy for Better Understanding: Solving a trigonometric proof is like navigating with a GPS. The Left-Hand Side (LHS) is your current location, and the Right-Hand Side (RHS) is your destination. In such cases, a student should always proceed looking and interpreting the RHS If you don’t keep looking at the destination on your map (the RHS), you might take many “correct” turns but still end up completely lost.
