JEE · Maths doubts
167 doubts found
What are the most common mistakes students make in Complex Numbers?
the product rule for surds doesn't hold for negatives; i·i = i² = −1.
How is Sequences & Series tested in JEE, and what should I focus on?
Prioritise the core ideas: Arithmetic progression, Geometric progression, Infinite geometric series.
What are the most common mistakes students make in Permutations & Combinations?
if rearranging the same items doesn't create a new outcome, use combinations, not permutations.
What are the most common mistakes students make in Trigonometry?
the range of both sine and cosine is [−1, 1] — a value outside means a mistake.
What are the most common mistakes students make in Straight Lines?
equal slopes make lines parallel; perpendicular slopes multiply to −1.
What are the most common mistakes students make in Conic Sections?
remember: circle e=0, ellipse 0<e<1, parabola e=1, hyperbola e>1.
How do I revise Limits & Continuity quickly before the exam?
One-page summary of Limit, Continuity, Standard limit, then timed previous-year questions.
What are the most common mistakes students make in Differentiation?
for composite functions you must multiply by the derivative of the inner function.
What are the most common mistakes students make in Integration?
every indefinite integral needs the arbitrary constant of integration.
What are the most common mistakes students make in Probability?
mutually exclusive events cannot both occur, so they are dependent, not independent.
What are the most common mistakes students make in Vectors & 3D Geometry?
the cross product is a VECTOR perpendicular to both inputs; the DOT product is the scalar.
How do I revise Quadratic Equations quickly before the exam?
One-page summary of Discriminant, Sum and product of roots, Nature of roots, then timed previous-year questions.
How do I revise Complex Numbers quickly before the exam?
One-page summary of The imaginary unit, Modulus and conjugate, Argand plane, then timed previous-year questions.
What are the most common mistakes students make in Sequences & Series?
the sum a/(1−r) exists only when |r|<1; otherwise the series diverges.
How do I revise Permutations & Combinations quickly before the exam?
One-page summary of Permutation, Combination, Fundamental principle of counting, then timed previous-year questions.
How do I revise Trigonometry quickly before the exam?
One-page summary of Pythagorean identity, Radians vs degrees, Range of sine and cosine, then timed previous-year questions.
How do I revise Straight Lines quickly before the exam?
One-page summary of Slope, Perpendicular and parallel lines, Equation forms, then timed previous-year questions.
How do I revise Conic Sections quickly before the exam?
One-page summary of Eccentricity, Focus and directrix, Standard equations, then timed previous-year questions.
How do I revise Differentiation quickly before the exam?
One-page summary of Derivative, Chain rule, Product and quotient rules, then timed previous-year questions.
How do I revise Integration quickly before the exam?
One-page summary of Antiderivative, Definite integral, Methods of integration, then timed previous-year questions.
How do I revise Probability quickly before the exam?
One-page summary of Basic probability, Independent vs mutually exclusive, Conditional probability, then timed previous-year questions.
How do I revise Vectors & 3D Geometry quickly before the exam?
One-page summary of Dot product, Cross product, Direction ratios, then timed previous-year questions.
How do I revise Sequences & Series quickly before the exam?
One-page summary of Arithmetic progression, Geometric progression, Infinite geometric series, then timed previous-year questions.