CBSE Class 11-science Answered
FIND
Asked by | 17 Sep, 2008, 07:40: PM
Expert Answer
x lies in third quadrant means pi ≤ x ≤3*pi/2
sinx = -4/5 (since sin is negative in this range)
then pi/2≤ x/2 ≤3*pi/4 and 2*pi≤ 2x ≤3*pi
we know that |cos x| = 2cos2 x/2 -1 => cos(x/2) = 2/
5
but since pi/2≤ x/2 ≤3*pi/4 in that range cos is negative cos(x/2) = -2/5
similarly sin is positive in both the range sin(x/2) = 1/5
and sin2x = 2 sinx cos x = 2(-3/5)(-4/5) = 24/25
Answered by | 18 Sep, 2008, 12:47: PM
Application Videos
-
Relation between roots and coefficient of a Quadratic E ...
Video contains the question based on quadratic equation where the relation ... -
Sum of infinite terms of an Arithmetic-Geometric Progre ...
Video contains the question based on how to find the sum of infinite terms ... -
Introduction to Locus of a point and its equation ...
Video contains the question based on finding equation of locus of a point -
Problems based on Equation of Locus of a Point ...
Video contains the question based on finding equation of locus of a poin...
-
Introduction to Translation of Axes and Problems based ...
Video contains the question based on translation of axes
Concept Videos
-
Trigonometric identities and problems
Fundamental trigonometric identities and problems based on them. Sign Conve... -
Degree measure and Radian measure ...
This video explains the concept of negative & positive angles, conversion o... -
Types of sets and its representation
Types of sets and describe two forms of set representation. -
Subsets and Supersets
This video covers the definition of subsets and supersets of a set and also... -
Representing the union and intersection of sets
Venn diagrams. Represent the union and intersection of sets with the help o...
CBSE 11-science - Maths
Asked by sampabarman328 | 18 Apr, 2024, 01:20: PM
ANSWERED BY EXPERTCBSE 11-science - Maths
Asked by tahikpreet0001 | 17 Apr, 2024, 06:41: AM
ANSWERED BY EXPERTCBSE 11-science - Maths
Asked by nitinkrjsr07082008 | 15 Apr, 2024, 11:32: PM
ANSWERED BY EXPERT
CBSE 11-science - Maths
Asked by kanhaparashar17 | 04 Apr, 2024, 12:55: PM
ANSWERED BY EXPERTCBSE 11-science - Maths
Asked by dseno1741 | 29 Mar, 2024, 08:47: PM
ANSWERED BY EXPERTCBSE 11-science - Maths
Asked by parvanipatil09 | 29 Mar, 2024, 10:12: AM
ANSWERED BY EXPERTCBSE 11-science - Maths
Asked by rishithatelaprolu84 | 29 Mar, 2024, 08:32: AM
ANSWERED BY EXPERTCBSE 11-science - Maths
Asked by Manjeet | 23 Mar, 2024, 09:41: PM
ANSWERED BY EXPERT
