Question
Show that:
tan10° tan15° tan75° tan80° = 1
tan10° tan15° tan75° tan80° = 1
✓
Answer
tan10° tan15° tan75° tan80° = 1
= tan(90°- 80°) tan(90° -75°) tan75° tan80°
= cot80° cot75° tan75° tan80°
= 1[As tanθ, cotθ = 1]
= tan(90°- 80°) tan(90° -75°) tan75° tan80°
= cot80° cot75° tan75° tan80°
= 1[As tanθ, cotθ = 1]
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
In the given figure, $AC$ is the diameter of circle, centre $O. CD$ and BE are parallel. Angle $AOB = 80^o$and angle $ACE = 10^o.$ Calculate: Angle $CED.$
→List the solution set of $\frac{11-2 x}{5} \geq \frac{9-3 x}{8}+\frac{3}{4}, x \in N$
→Take a point O on the plane at the paper. With O as center draw a circle of radius 3 cm. Take a point P on this circle and draw a tangent at P.
The internal and external diameters of a hollow hemi-spherical vessel are $21$ cm and $28$ cm respectively. Find: external curved surface area .
→In the figure, given below, find: ∠ ABC Show steps of your working.
$AC$ and $BD$ are two perpendicular diameter of a circle $ABCD.$ Given that the area of shaded portion is $308\ cm^2$ calculate:
(i) The length of $AC$ and
(ii) The circumference of circle
→(i) The length of $AC$ and
(ii) The circumference of circle
$\frac{2 x+3}{3} \geq \frac{3 x-1}{4}$ where $x$ is positive even integer.
→In ABCD is a cyclic quadrilateral in which ∠ DAC = 27° , ∠ DBA = 50° and ∠ ADB = 33°. Calculate ∠ DCB.
What number must be added to each of the numbers $6, 15, 20$ and $43$ to make them proportional?
→Solve the following equation: $4x^2 + 16x = 0$
→