show that root of equation Xe^x =1 lies between 0 and 1
Answers
Step-by-step explanation:
X.e^x = 1
X = e^-x
then X = + Infinity
it means there is no roots between 0,1
To Prove:
That the equation xeˣ = 1 has a root between 0 and 1.
Proof:
Let us assume y = xeˣ - 1 = f(x) i.e., y is a function of 'x'.
Now, we know that for a strictly increasing or decreasing function, a root lies between 'a' and 'b' only if f(a)f(b) < 0 i.e., f(a) and f(b) are of different signs.
Here, let us check if our function f(x) = xeˣ - 1 is a monotonic function or not.
So, To check the monotonicity of a function, we check it by calculating its differentiation.
∴ f(x) = (x + 1)eˣ
∴ f'(x) ≥ 0 for x ≥ -1
This proves that our function is strictly increasing in the region where we are going to check its root,
Now, f(0) × f(1) = (-1) × (e - 1)
i.e., f(0)f(1) = (1 - e) < 0
Hence, it is proved that the function f(x) has its root between 0 and 1.
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