Question

If cot (a - 18) = tan 2a, where 2a is acute angle. Find the value a

Answer 1

Step-by-step explanation:

ANSWER

Given tan2A=cot(A−18

0

)

⇒cot(90−2A)=cot(A−18

0

)[∵tanθ=cot(90−θ)]

Comparing angles we get

90−2A=A−18

⇒90+18=A+2A

⇒3A=108

⇒A=

3

108

⇒A=36

Answer 2

Answer:-

$\huge\sf{Given\:that,}$

$\longrightarrow$$\large\sf{tan\:2A=cot(A-18°)}$

$\longrightarrow$$\large\sf{cot(90°-2A)=cot(A-18°)}$

$\longrightarrow$$\large\sf{90°-2A=A-18°}$

$\longrightarrow$$\large\sf{108°=3A}$

$\longrightarrow$$\huge\sf{A=36°}$