## Some very important SLC questions

Short questions : Note This is just test; original post is here http://mb9851.wordpress.com/

Q. No .3
(i) If A+B = 45, prove that $(1+tanA)(1+tanB)=2$

(ii) If A+B = 45, prove that: $(cotA-1)(cotB-1) = 2$

(iii) If A+B =225, prove that $(tanA+1)(tanB+1)=2$

(ii) If A+B = 225, prove that: $(1-cotA)(1-cotB) = 2$

Q. No. 4 Prove that:

1. $(2cosA+1)(2cosA-1)=2cos2A+1$
2. $(2sinA-1)(2sinA+1)=1-2cos2A$
3. $(2cos{A \over 2}-1)(2cos{A \over 2}+1)=1+2cosA$
4. $(2sin{A \over 2} -1)(2sin {A \over 2} +1) = 1-2cosA$
5. $(2cos2A+1)(2cos2A-1)=1+2cos4A$
6. $(2sin2A -1)(2sin2A+1)=1-2cos4A$

### 4 Responses to “Some very important SLC questions”

1. bikash khulal Says:

if we want to go moon than we should go upwards from earth surface but again from moon we should go upwards to came earth.why the people go upwards?but earth lies down than moon?

2. bikash khulal Says:

why the position of hydrogen is not clear in modern periodic table law?

3. bikash khulal Says:

some law of newtons are going to be mistake.what a reason behind it?

4. ashish dahal Says:

That is because hydrogen has three isotopes i.e., protium, deutrium and tritium. Also, it has only one electron in its valance shell that makes it difficult to identify wheather it is a metal or a gas. Sometimes, it acts as metal, and sometimes as gas. For all reasons the position of hydrogen is not clear.