Question
Prove that:
$\sin(70^\circ+\theta)-\cos(20^\circ-\theta)=0$

Answer

$\text{L.H.S.}=\sin(70^\circ+\theta)-\cos(20^\circ-\theta)$
$=\sin\big\{90^\circ-(20^\circ-\theta)\big\}-\cos(20^\circ-\theta)$
$=\cos(20^\circ-\theta)-\cos(20^\circ-\theta)$
$=0$
$=\text{R.H.S.}$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

Very-Short and Short-Answer Questions.If $\text{x}=\text{a}\sin\theta$ and $\text{y}=\text{b}\cos\theta,$ write the value of $\Big(\text{b}^2\text{x}^2+\text{a}^2\text{y}^2\Big).$
Draw a circle of radius 2.7 cm. Draw a tangent to the circle at any point on it.
Prove : $\cos ^2 \theta+\frac{1}{1+\cot ^2 \theta}=1$
A spherical ball of radius 3cm is melted and recast into three spherical balls. The radii of two of these balls 1.5cm and 2cm. Find t radius of the third ball
Find the probability that a leap year selected at random will have 53 sundays.
An urn contains $10$ red and $8$ white balls. Write sample space $S$ and $n(S)$. Write the events $A$ and $B$ using Set and mention $n(A)$ and $n(B)$ if $A$ is the event that ball is white, $B$ is the event that ball is neither white nor red.
Show that the points $A(5, 6), B(1, 5), C(2, 1)$ and $D(6, 2)$ are the vertices of a square.
If the sides of a triangle are $3\ cm, 4\ cm$ and $6\ cm$ long, determine whether the triangle is a right-angled triangle.
A company provided Z-security services for the taxable value of Rs. 64,500. Rate of GST is 18%. Company had paid GST of Rs. 1550 for laundry services and uniforms etc. What is the amount of ITC (input Tax Credit)? Find the amount of CGST and SGST payable by the company.
A solid iron pole having cylindrical portion $110\ cm$ high and of base diameter $12\ cm$ is surmounted by a cone $9\ cm$ high. Find the mass of the pole, given that the mass of $1\ cm^3$ of iron is $8\ gm$.