Ashley Ting's answer to Imaboss's Secondary 4 E Maths Singapore question.

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Ashley Ting
Ashley Ting's answer
1 answers (Tutor Details)
1st
Hihi. Ok im not entirely sure what the ques wants for ii). So if u have the answer sheet, i cld take a look and maybe explain from there. If not, then :)))
Imaboss
Imaboss
4 years ago
Thanks
Imaboss
Imaboss
4 years ago
Thanks
Eric Nicholas K
Eric Nicholas K
4 years ago
I presume part b wants something like tan A = 2 tan B or something like that.

From part i,

3 cos A cos B = 5 sin A sin B

"Cross-dividing" cos B and cos A to the RHS ,

3/5 = tan A tan B

so the product of tan A and tan B is 3/5.
Imaboss
Imaboss
4 years ago
Thanks! Any ideas on part (3)
Eric Nicholas K
Eric Nicholas K
4 years ago
Use the formula which Ashley has written in part ii.

Note that the LHS becomes Tan 45 which equals 1.

Tan A Tan B is found in part ii.

The numerator is what we need to find, by substitution.