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junior college 1 | H2 Maths
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Candice
Candice

junior college 1 chevron_right H2 Maths chevron_right Singapore

Hello! How do i solve this qns? Sorry for all the differentiation qns, im having a bit of a struggle haha

Date Posted: 4 years ago
Views: 241
J
J
4 years ago
tan-¹x + tan-¹y + tan-¹xy = 7π/12

when x = 1,

tan-¹ 1 + tan-¹y + tan-¹y = 7π/12

π/4 + 2 tan-¹y = 7π/12

2 tan-¹y = π/3

tan-¹y = π/6

y = tan π/6

= 1/√3

= √3 / 3
J
J
4 years ago
tan-¹x + tan-¹y + tan-¹xy = 7π/12

Differentiating with respect to x,

1/(1 + x²) + 1/(1 + y²) dy/dx + d/dx (tan-¹xy) = 0

d/dx (tan-¹xy) = - 1/(1 + x²) - 1/(1 + y²)dy/dx
J
J
4 years ago
d/dx (tan-¹xy) = - 1/(1 + x²) - 1/(1 + y²)dy/dx

1/(1 + (xy)²) (y + x dy/dx) = - 1/(1 + x²) - 1/(1 + y²)dy/dx


When x = 1 , y = √3/3
(recall part i's working)

1/(1 + (√3/3)²) (√3/3 + dy/dx) = -1/(1 + 1²) - 1(1 + (√3/3)²) dy/dx

¾(√3/3 + dy/dx)= -1/2 - ¾ dy/dx

√3/4 + ¾ dy/dx = -½ - ¾ dy/dx

3/2 dy/dx = -½ - √3/4

dy/dx = -⅓ - √3/(2 x 3)

dy/dx = -⅓ - 1/2√3

(shown)
Candice
Candice
4 years ago
Thank you sm!!! :)

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Eric Nicholas K
Eric Nicholas K's answer
5997 answers (Tutor Details)
1st
Good evening Candice! Here is my working for part i.
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Eric Nicholas K
Eric Nicholas K's answer
5997 answers (Tutor Details)
Good evening Candice! Here are my workings for parts ii and iii.
Candice
Candice
4 years ago
Thank you! :")