Embibe Experts Solutions for Chapter: Introduction to Trigonometry, Exercise 1: Haryana Board-2018

Evaluate : $\frac{\sin 18°}{\cos 72°}$

In $△\mathrm{ABC},$ right-angled at $\mathrm{B}, \mathrm{AB}=24 \mathrm{cm}, \mathrm{BC}=7 \mathrm{cm}$. The value of $\sin \mathrm{A}$ is:

In $△\mathrm{OPQ}$ right-angled at $P, OP=7 \mathrm{cm} \mathrm{and} \left(OQ-PQ\right)=1 \mathrm{cm}$. Find the values of $\sin Q \mathrm{and} \cos Q$.

Prove that: 

${\left(\mathrm{cosec}\theta -\cot \theta \right)}^2=\frac{1-\cos \theta }{1+\cos \theta }$

If $\tan A=\frac{4}{3}$ then find $\cos A$

Find the value of $\sin 60°-\cos 30°$

Show that: $\tan 48°\tan 23°\tan 42°\tan 67°=1$

Prove that: ${\left(\mathrm{cosec}\theta -\cot \theta \right)}^2=\frac{1-\cos \theta }{1+\cos \theta }$