Analysis for Quiz 12: Brain Power Enrichment Quiz (I)
Question 1: If $a\gt b$ and $c\gt d$ are true, then we can say $a+c\gt b+d$ is always true.
A. Correct.
B. Incorrect.
Answer:
Yes, that is always correct, regardless if $a,\,b,\,c,\,d$ are negative or positive real number.
Take for example, we have:
A collection of intriguing competition level problems for secondary school students.
Showing posts with label A. Show all posts
Showing posts with label A. Show all posts
Thursday, July 30, 2015
Analysis for Quiz 12: Brain Power Enrichment Quiz (I)
Wednesday, June 10, 2015
Creative Solution for IMO Trigonometry Problem
Let $A,\,B$ be acute angles such that $\tan B=2015\sin A \cos A-2015\sin^2 A \tan B$.
Find the greatest possible value of $\tan B$.
This blog post is to highlight the fact that if we're creative enough, we can avoid the tedious calculus method to look for the maximal of $\tan B$.
You have to be aware of a few things as well:
1.
When $B$ is an acute angle and if $\sin B\le \dfrac{m}{n}$, then $\tan B\le \dfrac{m}{\sqrt{n^2-m^2}}$ must be true.
In other words, we obtain the maximal of $\tan B$ if we have obtained the maximal of $\sin B$.
Find the greatest possible value of $\tan B$.
This blog post is to highlight the fact that if we're creative enough, we can avoid the tedious calculus method to look for the maximal of $\tan B$.
You have to be aware of a few things as well:
1.
When $B$ is an acute angle and if $\sin B\le \dfrac{m}{n}$, then $\tan B\le \dfrac{m}{\sqrt{n^2-m^2}}$ must be true.
In other words, we obtain the maximal of $\tan B$ if we have obtained the maximal of $\sin B$.
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