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f-x-x-2-2x-6-x-1-x-4-2x-3-2-x-lt-1-show-that-there-is-a-number-c-2-3-such-that-f-c-4-




Question Number 90287 by jagoll last updated on 22/Apr/20
f(x) =  { ((x^2 −2x+6 , x≥1)),((x^4 +2x^3 +2 ,x<1)) :}  show that there is a number   c ∈ (−2,3) such that f(c) = 4
f(x)={x22x+6,x1x4+2x3+2,x<1showthatthereisanumberc(2,3)suchthatf(c)=4
Answered by MJS last updated on 22/Apr/20
x^2 −2x+6=4  x^2 −2x+1=−1  (x−1)^2 =−1  x∉R  x^4 +2x^3 +2=4  x^4 +2x^3 −2=0  g(x)=x^4 +2x^3 −2  g(−2)=−2<0  g(1)=1>0  ⇒ there must be at least one zero in [−2; 1]
x22x+6=4x22x+1=1(x1)2=1xRx4+2x3+2=4x4+2x32=0g(x)=x4+2x32g(2)=2<0g(1)=1>0theremustbeatleastonezeroin[2;1]

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