We use cookies to personalise content and advertisements and to analyse access to our website. Furthermore, our partners for online advertising receive pseudonymised information about your use of our website. cookie policy and privacy policy.
 
+0  
 
0
55
1
avatar

The expression: 8sin(\({\pi \over 3}\))cos(\({\pi \over 3}\))

 

I used the double angle identity  sin2A = 2sinAcosA but I'm not sure how I could get the textbook answer of 4sin(\({2 \pi \over 3}\))?

 Feb 20, 2019
 #1
avatar+18293 
+1

8 sin pi/3  cos pi/3           a = pi/3

4  * 2  sin pi/3  cos pi/3                    2 a will equal 2pi/3

 

 

In your identity      Sin2a = 2 sin a cos a       but your example is multiplied by 4

                              4 sin 2a = 4 * 2 sina cos a        See where the 4 comes from now?

                              4 sin (2pi/3)

 Feb 20, 2019

12 Online Users

avatar
avatar
avatar