Find the value of cos 100°×cos 40° + sin 100°×sin 40°
Answers
Answered by
0
Answer:
cos100
0
cos40
0
+sin100
0
sin40
0
This is in the form of cosAcosB+sinAsinB=cos(A−B)
Therefore, cos100
0
cos40
0
+sin100
0
sin40
0
=cos(100
0
−40
0
)
⇒cos100
0
cos40
0
+sin100
0
sin40
0
=cos60
0
⇒cos100
0
cos40
0
+sin100
0
sin40
0
=
2
1
Was this answer helpful?
Similar questions