Simplify each of the following expressions:
(i) (3 + √3)(2 + √2)
(ii) (3 + √3)(3 - √3)
(iii) (√5 + √2 )2
(iv) (√5 - √2)(√5 + √2)
(i) (3 + √3)(2 + √2) = 3(2 + √2) + √3 (2 + √2)
= 6 + 3√2 + 2√3 + √6
(ii) (3 + √3) (3 - √3) = (3)2 - (√3)2
= 9 - 3 = 6
(iii) (√5 + √2)2 = (√5)2 + (√2)2 + 2(√5)(√2)
= 5 + 2 + 2√10
7 + 2√10
(iv) (√5 - √2)(√5 + √2) = (√5)2 - (√2)2
= 5 - 2 = 3
For real number a, b (a > b > 0), let
\(\text{{Area}} \left\{ (x, y) : x^2 + y^2 \leq a^2 \text{{ and }} \frac{x^2}{a^2} + \frac{y^2}{b^2} \geq 1 \right\} = 30\pi\)
and
\(\text{{Area}} \left\{ (x, y) : x^2 + y^2 \geq b^2 \text{{ and }} \frac{x^2}{a^2} + \frac{y^2}{b^2} \leq 1 \right\} = 18\pi\)
Then the value of (a – b)2 is equal to _____.
In Fig. 9.26, A, B, C and D are four points on a circle. AC and BD intersect at a point E such that ∠ BEC = 130° and ∠ ECD = 20°. Find ∠ BAC.
Look up the dictionary entries for the words sympathy, familiarity, comfort, care, and surprise. Use the information given in the dictionary and complete the table.
Noun, Adjective, Adverb, Verb, Meaning:
sympathy
familiarity
comfort
care
surprise