Find the tenth term of the sequence: 1, -2, 4, -8, …

**Solution:-**

Find the common ratio and use the explicit formula for geometric sequences:

a_{n} = a_{1} r^{n-1}

a_{1} = 1 and r = -2

the tenth term = 1 *-2^{10-1}

= -512

Skip to content
# Problem 688

learn maths and leave the fear of it

Find the tenth term of the sequence: 1, -2, 4, -8, …

**Solution:-**

Find the common ratio and use the explicit formula for geometric sequences:

a_{n} = a_{1} r^{n-1}

a_{1} = 1 and r = -2

the tenth term = 1 *-2^{10-1}

= -512