# If A = 30°; show that: 1 – cos 2 A sin 2 A = tan A - Mathematics

Sum

If A = 30°;
show that:
(1 – cos 2"A")/(sin 2"A") = tan"A"

#### Solution

Given that A = 30°

LHS = (1 – cos2 "A")/(sin 2"A")

= (1 – cos 2 (30°))/(sin2 (30°))

= (1 – (1)/(2))/((sqrt3)/(2)

= (1)/(sqrt3)

RHS = tan A

= tan 30°

= (1)/(sqrt3)

LHS = RHS

Concept: Trigonometric Ratios of Some Special Angles
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#### APPEARS IN

Selina Concise Mathematics Class 9 ICSE
Chapter 23 Trigonometrical Ratios of Standard Angles [Including Evaluation of an Expression Involving Trigonometric Ratios]
Exercise 23 (B) | Q 4.4 | Page 293
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