A person can see up to 4m clearly, but can`t see up to 4 m. What is the power of lens required to see the object at 20 m.?

My rank is 29k, General, should I opt for any state college cse branch or some Nits in which in which I am getting ECE , chemical, mechanics etc....

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Can class 9th students study syllabus classof 11th

Sum of series 2[n/2] ! [n/2]!/ n! [2Co-2C2+3C2....+[-1]^n[n+1]2Cn] where n is an even positive integer. Kindly provide solution of this question and how to generalise this. How do we know that which expansion will give this?

I m foreigner,How much mark i need to get into IIT??