find the value of cos^2tetha +sin^2tetha if in triangle abc,angle c =90° and angle b=tetha
Answers
Answered by
0
Answer:
answr
search
What would you like to ask?
10th
Maths
Introduction to Trigonometry
Trigonometric Ratios
Consider ACB , right angle...
MATHS
avatar
Asked on December 27, 2019 by
Angelic Kaushal
Consider △ACB, right angled at C, in which AB=29 units, BC=21 units ∠ABC=θ. Determine the value of
(i) cos
2
θ+sin
2
θ
(ii) cos
2
θ−sin
2
θ
EASY
Share
Study later
ANSWER
By Pythagoras theorem,
AB
2
=AC
2
+BC
2
⇒AC
2
=AB
2
−BC
2
⇒AC
2
=29
2
−21
2
=(29+21)(29−21)=50×8
⇒AC
2
=25×16
⇒AC=5×4=20 units
⇒cosθ=
AB
BC
=
29
21
,
sinθ=
AB
AC
=
29
20
⇒sin2θ+cos
2
θ=
29
2
21
2
+20
2
=
29
2
29
2
=1
⇒cos
2
θ−sin
2
θ=
29
2
21
2
−20
2
=
841
41
.
solution
Similar questions