Question

Choose the correct Sum Formula for cos(35) using 15 and 20.

Answer 1

Given:

We have Cos 35 degree.

Required:

Choose the correct Sum Formula.

Explanation:

We will use

$Cos(A+B)=CosACosB-SinASinB$

Now, We can write Cos (35) as Cos(20 + 15)

$\begin{gathered} Cos(20+15)=Cos20Cos15-Sin20Sin15 \\ =0.819 \end{gathered}$

Answer:

Hence, question is solved.