Q:determine the range of y=2x/(4-x)
我是把他化成y=-2 + 8/(4-x)
這樣看起來值域是(-無限大, 無限大)?
x=4.1 y=-82
x=3.9 y=78
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還請各位指正...
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另一提:show that every function defined
for all real numbers can be written
as the sum of an even function
and an odd function.
設f(x)=a0+a1x+a2x^2+a3x^3+...
設g(x)=f(x)+f(-x)
=2a0+2a2x^2+2a4x^4+...
→g(x)屬於偶函數
設h(x)=f(x)-f(-x)
=2a1x+2a3x^3+2a5x^5+...
→h(x)屬於奇函數
f(x)又可寫成 [f(x)+f(-x)]/2 + [f(x)-f(-x)]/2
=g(x)/2 + h(x)/2
故得證
不知是哪裡不夠嚴謹或需修改
煩請指正