# Show that the function #f(x)=4x^2-5x# has a zero between #1# and #2#.

##### 2 Answers

As the value of function

#### Explanation:

The function is

Its derivative being

Further, at

At

It is obvious that between

We may apply the Bolzano Theorem

**Bolzano Theorem (BT)**

Let, for two real a and b, a < b, a function f be continuous on a closed interval [a, b] such that f(a) and f(b) are of opposite signs. Then there exists a number

Hence we have that

Because