What does the law of cosines reduce to when dealing with a right triangle

Pythagorean theorem

Step-by-step explanation:

We know that for a triangle if we know two sides and the included angle, the third side can be found out using cosine formula

For a right angle triangle right angled at A this becomes

This is nothing but Pythagorean theorem

see explanation

step-by-step explanation:

since the sequence is geometric there is a common ratio r between consecutive terms, that is

r = 4 ÷ - 2 = - 2

r = - 8 ÷ 4 = - 2

r = 16 ÷ 8 = - 2

the next term - 13 must be incorrect as it should be - 32 for the sequence to be geometric.

the first 4 terms are therefore geometric with common ratio r = - 2