Use the Intermediate Value Theorem to answer the following a

Use the Intermediate Value Theorem to answer the following:
(a) Is there any root for the equation x+sin x = x2? If so, indicate an interval
containing a root.
(b) Is there a number which is exactly 1 more than its cube? If so, indicate
an interval containing such a number.

Solution

x + sinx = x2

f(x) =   x + sinx - x2

f(0) = 0          it satisfies !!!

f(1) =     1 + sin 1 - 1 = sin 1 (+ve number)

f(2) =    2 - 4 + sin2 = sin2 - 2 (-ve number)

hence there is also a root in (1,2) interval

b) x = x3 + 1

f(x) = x - x3 - 1

f(0) = -1

f(1) = -1

f(-1) = -1 + 1 -1 = -1    -ve number !!!

f(-2) = -2 + 8 - 1 = 5   +ve number !!1

using intermediatw theorem : (-2, -1)   there is a root in this interval 1!!

Use the Intermediate Value Theorem to answer the following: (a) Is there any root for the equation x+sin x = x2? If so, indicate an interval containing a root.

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