If sin 3y = cos 2y and 0 o \(\leq\) 90 o , find the

MATHEMATICS

WAEC 2010

If sin 3y = cos 2y and 0^o \(\leq\) 90^o, find the value of y

A. 18°
B. 36°
C. 54°
D. 90°

Correct Answer: A. 18°

Explanation

sin 3y = cos 2y, but sin \(\theta\) = cos(90 - \(\theta\))

sin 3y = cos(90 - 3y)

cos(90 - 3y) = cos 2y

90 - 3y = 2y

5y = 90

y = \(\frac{90}{5}\)

y = 18^o

Previous Next

Back to WAEC 2010 Questions

Post an Explanation Or Report an Error

If you see any wrong question or answer, please leave a comment below and we'll take a look. If you doubt why the selected answer is correct or need additional more details? Please drop a comment or Contact us directly. Your email address will not be published. Required fields are marked *