# If sec A = cosec A and 0° ∠A ∠90°, state the value of A - Mathematics

Sum

If sec A = cosec A and 0° ∠A ∠90°, state the value of A

#### Solution

sec A = cosec A
cos A = sin A
cos2A = sin2A
cos2 A = 1 – cos2A
2cos2A = 1

cos A = (1)/(sqrt2)
A = 45°

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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 (A) | Q 7.2 | Page 291