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In triangle ABC , right angled at c in which AB=29units , BC=21units and angle ABC= THETA . determine1. cos^2 theta + sin^2 theta2. cos^2theta-sin^2theta3. tan^2theta-sec^2theta |
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Answer» Answer: 41/841 Step-by-step explanation: 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 |
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