for a, i know you can prove it exists because it's between -1 and 2
but i literally cannot find anywhere that explains how to find what it actually is so i have no idea how to answer B
can anyone help me with this?

so IVT just states that a root exists if the function is continuous and passes the x-axis.
So for B we want to reduce the interval of the function until we can approximate where the root is (> 1.5 or < 1.5)
To do this you just average [a,b]
so (1 + 2) / 2 = 1.5. then you take f(1.5)
If f(1.5) is negative it replaces a like so: [1.5, 2]. If it's positive it replaces b like so [1, 1.5] . If f(1.5) = 0 then it is the root.

Looks like B only requires this 1 step. as with just this you will find if it's between 1.5 and 2 or 1 and 1.5.

But you can continue doing this. Finding the midpoint. Eventually the midpoint will be 0 (or VERY close to it) and you will have almost the exact answer for the root.

This post was edited by kasey21 on Jan 30 2019 07:22pm