wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

If 0<β<α<π2,cos(α+β)=35andcos(α-β)=45, then sin2α is equal to.


A

0

No worries! We‘ve got your back. Try BYJU‘S free classes today!
B

1

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
C

2

No worries! We‘ve got your back. Try BYJU‘S free classes today!
D

Noneofthese

No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is B

1


Step 1. Framing equations

Given, cos(α+β)=35&cos(α-β)=45

Now,

cos(α+β)=35

(α+β)=cos-1(35)…..(i)

cos(α-β)=45

sin(α-β)=35

(α-β)=sin-1(35)…..(ii)

Step 2. Add equation (i) & (ii), we get

α+β+α-β=cos-1(35)+sin-1(35)

2α=π2

sin2α=sinπ2=1

Hence, correct option is (B)


flag
Suggest Corrections
thumbs-up
2
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Integration of Trigonometric Functions
MATHEMATICS
Watch in App
Join BYJU'S Learning Program
CrossIcon