CameraIcon
CameraIcon
SearchIcon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

Consider the quadratic equation x2+2xsina+cosa+1=0,aR. If
D denotes the discriminant of the given quadratic equation, then which of the following is/are correct?

A
Maximum value of D is 8
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
Minimum value of D is 8
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
C
Maximum value of D occurs when cosa=0
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
Maximum value of D occurs when cosa=12
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
Open in App
Solution

The correct options are
B Minimum value of D is 8
D Maximum value of D occurs when cosa=12
x2+2xsina+cosa+1=0
D=4sin2a4cosa4 =44cos2a4cosa4 =14(cos2a+cosa+14) =14(cosa+12)2

Now,
1cosa112cosa3294(cosa+12)2094(cosa+12)20814(cosa+12)218D1

So, Dmin=8, when cosa=1

So, Dmax=1, when cosa=12

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
similar_icon
Related Videos
thumbnail
lock
Range of Trigonometric Expressions
MATHEMATICS
Watch in App
Join BYJU'S Learning Program
CrossIcon