In triangle ABC, we have ab=5, bc= 8 and ac=7, as shown below:
Calculate
\(\cos (\angle A), \cos (\angle B), \cos (\angle C)\)
and enter them in that order.
Use the Cosine rule: \(\cos A = \frac{b^2+c^2-a^2}{2bc}\)
Here: a = 8, b = 7, c = 5
Cycle a, b and c for the other angles.
Hello, how whould I get cosb and c then?
For cos B change the formula so that A → B, a → b, b → c, c → a
See if you can then work out what to do for cos C.
