Question

please do this like I can understand. For class 9​

Answer 1

we know that tanA = 1/cot A......(1)

cotA + tanA = 1

squaring on both sides

(cotA + tan A)² = 1²

using property

(a+b)² = a²+b²+2ab

cot²A + tan² A + 2× tanA ×cotA = 1

cot²A + tan²A+2×(1/cotA )× cotA=1

cot²A + tan²A +2 =1

cot²A + tan²A = 1-2 = -1

cot²A +tan²A = -1