Question

12. If A+B+C=180° then prove the following:
i) cos A + cos(B-C) = 2 sin B sin C
A
B-C
B C
ii) cos—+sin
=2 sin-cos
=
2
2
2 2
A B
iii) tantan
= 1 if A, B, C are positive.
A, .
2 2​

Answer 1

Step-by-step explanation:

The COVID-19 pandemic has led to a dramatic loss of human life worldwide and presents an unprecedented challenge to public health, food systems and the world of work. The economic and social disruption caused by the pandemic is devastating: tens of millions of people are at risk of falling into extreme poverty, while the number of undernourished people, currently estimated at nearly 690 million, could increase by up to 132 million by the end of the year.