Advertisements
Advertisements
Question
The value of tan 72° tan 18° is
Options
0
1
18°
72°
Advertisements
Solution
1
Explanation;
Hint:
tan 72° . tan 18° = tan 72° . tan (90° – 72°)
= tan 72° . cot 72°
= `tan 72^circ xx 1/tan 72^circ`
= 1
APPEARS IN
RELATED QUESTIONS
if `cosec A = sqrt2` find the value of `(2 sin^2 A + 3 cot^2 A)/(4(tan^2 A - cos^2 A))`
solve.
sec2 18° - cot2 72°
Evaluate:
`cos70^circ/(sin20^circ) + cos59^circ/(sin31^circ) - 8 sin^2 30^circ`
Use tables to find cosine of 2° 4’
Evaluate:
`sec26^@ sin64^@ + (cosec33^@)/sec57^@`
Prove that:
sin (28° + A) = cos (62° – A)
If A and B are complementary angles, prove that:
cot B + cos B = sec A cos B (1 + sin B)
If the angle θ = –45° , find the value of tan θ.
Write the acute angle θ satisfying \[\cos B = \frac{3}{5}\]
If θ is an acute angle such that \[\tan^2 \theta = \frac{8}{7}\] then the value of \[\frac{\left( 1 + \sin \theta \right) \left( 1 - \sin \theta \right)}{\left( 1 + \cos \theta \right) \left( 1 - \cos \theta \right)}\]
