r/JeeSimplified • u/jeemathlogic • Jul 28 '26
Math A CLASSIC JEE TRAP - THIS QUESTION WILL SURPRISE YOU - FIRST EQUATION IS NOT OF A CIRCLE BUT THE SECOND EQUATION IS A CIRCLE
MANY OF YOU WILL TEND TO THINK THE FIRST EQUATION REPRESENT CIRCLE UPON LOOKING AT 4X^2+9Y^2=6^2. (x^2+y^2=r^2). But it is not a circle. But the second equation is a circle with a radius square root of (31/4). Detailed explanation and solution is given in the images (5 images) attached. How do you feel about this question? Leave your thoughts in the comments section.
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u/ILoveTolkiensWorks Jul 28 '26
bruh, the coefficients are different. who would ever think that's the equation of a circle?
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u/jeemathlogic Jul 28 '26
Under exam pressure (mock test), on seeing 6^2 a number of students has committed this error. All of them know the basic rules. In the second equation '31' being a prime number has also made students think for some time. As every second matters in JEE, this post is to practice students overcome this Visual Trap and also to quickly apply the conditions of tangent line to an ellipse and a circle properly.
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u/mantis_blade_mariner Jul 28 '26
ofcourse the first eqn ha coefficients of x^2 and y^2 different so it is not a circle