The first term of the sequence is 2. every term after is -2 multiplied by the preceding term. How many of the first 50 terms of this sequence are less than 100?
Explain process

Question

The first term of the sequence is 2. every term after is -2 multiplied by the preceding term. How many of the first 50 terms of this sequence are less than 100?
Explain process

anonymous · Answer

ex. 2, -4, 8, ...

lgbasallote · Answer

you know the formula for geometrick sequence right?

anonymous · Answer

yes, but how would you put that into a calculator as a linear sequence? (no piecewise)

lgbasallote · Answer

hmm this can be hard =_=

anonymous · Answer

yes, it is unless you do it by hand

anonymous · Answer

The first 6 terms
{2, -4, 8, -16, 32, -64} are all less then 100
For the rest only the negative ones are less than 100.

anonymous · Answer

Here they are 
{-256, -1024, -4096, -16384, -65536, -262144, -1048576, -4194304, \
-16777216, -67108864, -268435456, -1073741824, -4294967296, \
-17179869184, -68719476736, -274877906944, -1099511627776, \
-4398046511104, -17592186044416, -70368744177664, -281474976710656, \
-1125899906842624}
There are 22 of them.
In total 22+6=28