If f(x+y)=f(x)+f(y)+2xy & f’(0)=2, then f’(3)=? Ft @lihanmath @bprpcalcbasics
If f(x+y)=f(x)+f(y)+2xy & f’(0)=2, then f’(3)=? Ft @lihanmath @bprpcalcbasics
Uploaded August 2026 | Updated September 2026, 2 weeks ago
Here’s a classic functional equation f(x+y)=f(x)+f(y)+2xy and special thanks to ​⁠Mr. Li from Taiwan @lihanmath for showing us a clever calculus trick!

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If f(x+y)=f(x)+f(y)+2xy & f’(0)=2, then f’(3)=? Ft @lihanmath

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