Question

9(secA.secA-tanA.tanA)is equals to

Answer 1

Answer:

9(sec^2A - tan^2A)

sec^2A = 1+tan^2A

sec^2A -tan^2A = 1

9(1) = 9

Answer 2

Answer:

9

Step-by-step explanation:

9 [(secA)² - (tanA)²]

= 9 [(secA) + (tanA)] * [ [(secA) - (tanA)] ...................[Formula $a^{2} - b^{2}$]

= 9 [$\frac{1}{cosA}$ + $\frac{sinA}{cosA}$] * [$\frac{1}{cosA}$ - $\frac{sinA}{cosA}$]

= 9 [ $\frac{1 + sinA}{cosA}$] * [$\frac{1-sinA}{cosA}$]

= 9 [1 - $sin^{2}$A / $cos^{2}$A]

= 9 [$cos^{2}A$ / $cos^{2}A$] .........................(Used $cos^{2}A$ + $sin^{2}A$ = 1]

= 9