Abhijit

 23 What would have been our number system if humans had more than 10 fingers? Try to solve this puzzle. 22 Solve $\cos^2x-\sin^2x= 1$ 15 How to find the value of $\sin{\dfrac{\pi}{14}}+6\sin^2{\dfrac{\pi}{14}}-8\sin^4{\dfrac{\pi}{14}}$ 10 Trying to find a function whose derivative is $\cfrac{4x^3}{x^4+1}$ any ideas? 9 How can I prove that $xy\leq x^2+y^2$?

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### Questions (7)

 11 How to prove $\cos\left(\pi\over7\right)-\cos\left({2\pi}\over7\right)+\cos\left({3\pi}\over7\right)=\cos\left({\pi}\over3 \right)$ 3 Angles between vectors using a non-standard inner product 2 How do you determine if a function is nonelementary antiderivative [duplicate] 1 Determine number of squares in progressively decreasing size that can be carved out of a rectangle 0 Concept: Multiplying a vector by a scalar quantity

### Tags (48)

 65 algebra-precalculus × 16 14 calculus × 6 54 trigonometry × 7 10 real-analysis × 4 31 puzzle × 3 9 inequality 31 number-systems × 3 8 geometry × 7 18 derivatives × 4 8 quadratics

### Bookmarks (1)

 239 The Integral that Stumped Feynman?