CBSE BOARD XII, asked by sonalnagar27, 1 year ago

find the value of ( 1+sec 20°+ cot 70°)(1-cosec 20°+ tan 70°)

Answers

Answered by anjalisingh558pdkbpe
0

ec 20= 1/cos 20=1/sin 70

cot 70= cos 70/sin 70

cosec 20= 1/sin 20= 1/cos 70


(1+sec 20 + cot 70)=1+1/sin 70+ cos 70/sin 70

take lcm

(sin 70+1 + cos 70)/sin 70

similarly

(1-cosec 20+ tan 70)= (cos 70-1+ sin 70)/sin 70

multiple both


(sin70 cos70- sin 70+sin^2 70+ cos 70-1+sin70+

cos^2 70- cos 70+ sin70 cos 70)/ sin70 cos70


(2sin 70 cos 70)/ sin70 cos 70=2

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